Cross-sectional study on public health knowledge among first-year university students in Japan: Implications for educators and educational institutions

Abstract

In recent years, there have been increasing knowledge gaps and biases in public health information. This has become especially evident during the COVID-19 pandemic and has contributed to the spread of misinformation. With constant exposure to disinformation and misinformation through television, the internet, and social media, even university students studying healthcare-related subjects lack accurate public health knowledge. This study aimed to assess university students’ knowledge levels of basic public health topics before they started their specialized education. Participants in this cross-sectional study were first-year students from medical schools, health-related colleges, and liberal arts colleges. A self-administered electronic survey was conducted from April to May 2021 at a private university in Japan, comprising six colleges with seven programs. Data analysis, conducted from June to December 2022, included students’ self-reported public health knowledge, sources of information, and self-assessment of knowledge levels. Among the 1,562 students who received the questionnaire, 549 (192 male [35%], 353 female [64.3%], and 4 undisclosed [0.7%]) responded to one question (participants’ response rate for each question; 59.6%–100%). The results showed that students had limited public health knowledge, especially in sexual health topics, and 10% of students reported not learning in class before university admission the following 11 topics: two on Alcohol, Tobacco, and Other Drugs; eight on Growth, Development, and Sexual Health; and one on Personal and Community Health. These results indicate significant knowledge gaps and biases, as well as gender gaps, in public health education, especially in the area of sexual health, which may help educators and educational institutions to better understand and prepare for further specialized education. The findings also suggest a need to supplement and reinforce the foundation of public health knowledge for healthcare majors at the time of university admission.

Introduction

Public health knowledge is vital for a healthy society. In recent years, there has been a surge in the prevalence of sexually transmitted diseases (STDs) in industrialized countries [1–5], including Japan [6, 7]. This increase has been further exacerbated during the COVID-19 pandemic. The increase in STDs among females in their 20s and 30s, especially the prevalence of Chlamydia infections among females in their teens, is particularly notable in Japan [8, 9]. STD prevention is an integral part of public health, and it is taught in health and physical education in Japan. Historically, sexual education as an essential ingredient of health and physical education changed from “non-existent” to “teaching chastity” in 1949, after which sex-segregated sexual education was mainly concerned with physiological differences or merely teaching about menstruation, which further evolved to somewhat sex-integrated education in Japan only in recent years [10, 11]. Although strides have been made in addressing crucial subjects such as gender equality, social justice, reproductive rights, and public health education, female students still show preference for single-sex sexual education and female educators. In the presence of other sexes in the same room, sexual health can be uncomfortable to discuss or study [12], which makes conversations among them more challenging.

According to previous studies, there is a notable difference between the genders in their preferred sources of knowledge regarding sexual health. Female students’ ideal source of information was reported to be school as the primary source, followed by parents, friends, and the Internet. In contrast, male students preferred school as the primary source, followed by the Internet, friends, and parents, suggesting that there might be a difference in sexual education needs at home between male and female students [13]. Although diverse information sources generally mean more accurate knowledge of sexual health [14], not all information sources provide accurate information [15, 16], especially information sources such as the internet. Internet-based information could potentially be harmful due to the presence of inaccurate, misleading, or incomplete information based on insufficient or unsubstantiated “scientific” evidence or even sensational, anecdotal views [16]. In fact, people with lower health literacy were more likely to use and trust health information from social media, blogs, or celebrity webpages [17].

Education regarding STD prevention and basic public health education is included in the standard curriculum guidelines issued by the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) under Health and Physical Education in Japan [18, 19]. However, health and sexual health education are not necessarily required for enrollment in any college because health topics are not included in entrance exams, leaving the extent of public health topics to each educator’s discretion prior to university enrollment. This possible lack of public health education also applies to students enrolled in healthcare-related universities.

Healthcare professionals are required to disseminate this information. The lack of or inaccurate knowledge of public health among healthcare professionals has a direct effect on the public. However, obtaining accurate health information is not necessarily easy for people of different social and economic backgrounds or even sexes. It has been reported that there are digital disparities, in which higher socio-economic status and higher education are factors positively associated with digital health information seeking, which could result from either a disparity of access or a disparity of literacy and comprehension [15, 16, 20]. Gender gaps exist in education [21, 22]. Additionally, other factors affecting public health knowledge exist, including promoting abstinence-only education, the lack of sexual health education altogether, or even the discouraging of its provision [23, 24]. The disparities in public health knowledge have been accentuated and brought to the forefront amidst the backdrop of the COVID-19 pandemic. This global crisis has magnified the existing gaps and biases, leading to the proliferation of misinformation and exacerbating knowledge disparities. A prominent consequence of this phenomenon has been the emergence of vaccine hesitancy, despite the development and widespread distribution [25, 26] of COVID-19 vaccines [27]. With constant exposure to disinformation and misinformation through television, the Internet, and social media [15, 28], it is imperative that younger generations, especially future healthcare providers, are given accurate health information that is the best available at the time.

Since the establishment of health promotion in the 1986 Ottawa Charter by the World Health Organization in Ottawa, Canada [29], numerous studies, reports, and surveys have been conducted on sexual education worldwide. However, it is unknown whether future healthcare professionals will acquire adequate health and public health knowledge before enrolling in university.

In this study, we surveyed healthcare-related college students to assess their level of public health knowledge and evaluate whether they have adequate knowledge before proceeding to specialized education in healthcare-related universities. The findings of this study can be beneficial for educators to supplement the gap in students’ essential knowledge, especially healthcare-related college students, in the aftermath of the COVID-19 pandemic.

Materials and methods

Study design and participants

We developed a self-administered questionnaire designed to assess and evaluate first-year university students’ knowledge of public health topics and conducted a cross-sectional study at Juntendo University, Tokyo, Japan. In order to assess public health knowledge prior to university with minimal influence of health-related knowledge from university classes, we selected first-year students within two months of admission to Juntendo University. Juntendo University is a private university that focuses on health science, comprising six colleges with seven programs: medicine, health care and nursing, health science and nursing, health science/radiological technology, health science/physical therapy, health and sports science, and international liberal arts. Table 1 presents the program characteristics.

Table 1. Basic characteristics of participants (n = 549).

Colleges	Characteristics of colleges	Total (%)	Sex
			Male (%)	Female (%)	Undisclosed (%)
Medicine	Private medical school established in 1838, headquarters in Tokyo	74(13.5)	37(50)	37(50)	0(0)
Health Care and Nursing	Nursing course serving greater Tokyo area	63(11.5)	1(1.6)	61(96.8)	1(1.6)
Health Science and Nursing	Nursing course serving in the local area community of Shizuoka prefecture	90(16.4)	6(6.7)	84(93.3)	0(0)
Health Science/Physical Therapy	Training course for physical therapists	83(15.1)	29(34.9)	54(65.1)	0(0)
Health Science/ Radiological Technology	Training course for radiological technologists	30(5.5)	9(30)	20(66.7)	1(3.3)
Health and Sports Science	Six courses related to sports. e.g., athlete, sports management, coaching, etc.	159(29)	94(59.1)	64(40.3)	1(0.6)
International Liberal Arts	Courses on global sociological issues, intercultural communication, global health service	50(9.1)	16(32)	33(66)	1(2)
Total		549(100)	192(35)	353(64.3)	4(0.7)

NOTE. Values in parenthesis represent percentage of valid total N.

We distributed web-based questionnaires to the entire cohort of first-year students (n = 1,562) across seven programs at Juntendo University. We utilized the university’s universal message system to distribute the questionnaires among the different program divisions: Medicine (n = 136), Healthcare and Nursing (n = 204), Health Science and Nursing (n = 127), Health Science/Physical Therapy (n = 121), Health Science/Radiological Technology (n = 121) Health and Sports Science (n = 608), and International Liberal Arts (n = 245). This survey was conducted between April and May 2021. All participants provided informed consent and had the option to decline participation. Prior to their involvement, participants received a comprehensive overview of the study, including detailed information about data management procedures. They were informed that their data would be anonymized and participation was voluntary. We obtained informed consent from respondents by asking to tick the checkbox in the survey and collected the completed questionnaires. Respondents who did not provide informed consent were excluded from the study. Parental consent was not required since first-year students in Japan are 18 years of age or older. There were no other exclusion criteria.

Questionnaire and survey

To examine the differences in students’ awareness and knowledge of health and public health, we identified essential topics and public health knowledge from the Japanese curriculum guidelines, educational policies, educational contents of textbooks, and standard health education policies stipulated by the Centers for Disease Control and Prevention (CDC). We selected several crucial health education sections and topics shared by Japan and the United States: 1) Nutrition and Physical Activity; 2) Growth, Development, and Sexual Health; 3) Injury Prevention; 4) Alcohol, Tobacco, and Other Drugs; 5) Mental and Social Health; and 6) Personal and Community Health. We identified 31 knowledge topics for the educational content, which are listed in S1 Table. For each of these knowledge topics, we developed a set of three self-assessment questions, including: 1) the presence/absence of knowledge (acquired in class); 2) information sources for the knowledge; and 3) the level of knowledge on a 10-point scale ranging from 1 (no knowledge at all) to 10 (enough knowledge to teach someone else). In total, we prepared 86 self-assessment questions. We prepared five questions on knowledge of lifestyle-related diseases, contraception, LGBTQIA+ issues, pathogens causing infections, and transmission of infection, for a total of 91 questions (S2 Table). We developed the survey questions in consultation with medical and health education experts. We prepared a survey using Google Forms and administered it to all freshmen in all departments. All survey data was collected anonymously. The questionnaires included self-reported sex (i.e., male, female, undisclosed, or other). With a racially homogeneous environment and most university enrollment occurring immediately after high school, we did not ask about ethnicity or age to maintain anonymity. We consulted with two native English bilinguals and two native Japanese bilinguals to translate the questions and answers.

Data analysis

Descriptive analyses were performed to examine the respondents’ characteristics and responses. Frequencies and percentages were utilized for categorical variables, and means and standard deviations, or medians and 95% confidence intervals were utilized for continuous variables. If there was at least one answer to a question, the answer was accepted. Unless otherwise stated, the percentage was calculated based on the number of responses to each question. The number of topics for which students reported having knowledge and self-assessment knowledge levels was calculated as a percentage of the total knowledge score and total knowledge self-assessment score, and normality was tested using the Shapiro-Wilk test. The maximum score for total knowledge and self-assessment are 29 and 290, respectively. We converted the total knowledge score and self-assessment score into percentage scores, with a maximum attainable score of 100%. To evaluate knowledge level and self-assessment levels across colleges, we categorized scores below the 25th percentile as “Poor,” scores between the 25th and 75th percentile as “Fair,” and scores at or above the 75th percentile as “Good.” We examined the total knowledge and self-assessment scores, as well as the categorization of these scores into three levels (“Poor,” “Fair,” “Good”), using appropriate methods. Specifically, we employed Kruskal–Wallis tests for non-parametric variance analysis, performed one-way analysis of variance for parametric variance assessment, employed Pearson Chi-Square Tests for proportions, and conducted Bonferroni adjusted pairwise comparisons. These analyses aimed to evaluate whether statistically significant differences existed between colleges regarding knowledge and self-assessment levels. The undisclosed sex group was excluded from the examination based on sex comparison. The Pearson’s chi-square test was used to examine sex-based differences. Z-tests were used to further explore the differences, and the Bonferroni correction was employed to adjust for multiple comparisons. Mann-Whitney U tests were used to examine the mean rank differences in self-assessment by sex. Given the available resources and constraints in data collection, we gathered data from 549 first-year students, representing a subset of the total population of 1,562 first-year students within the university. As such, a formal sample size calculation or power analysis was not conducted because of the exploratory nature of this study and the comprehensive distribution of the questionnaire to the total first-year student population at Juntendo University.

All statistical analyses were performed using IBM SPSS Statistics for Windows, Version 28.0 (Armonk, NY: IBM Corp.). The p-value threshold for significance was adjusted for multiple comparisons using the Bonferroni correction. The threshold for statistical significance was set at p < .05.

Ethics statement

This study was approved by the Juntendo University Ethical Review Board (No. 2020324) and followed the Strengthening the Reporting of Observational Studies in Epidemiology Reporting Guidelines. We obtained informed consent from respondents and collected the completed questionnaires.

Results

Response

Among the 1,562 students who received the questionnaires, 549 (35.15%) responded to at least one question (response rate: total 35.1%, medicine 54.4%, healthcare and nursing 30.9%, health science and nursing 70.9%, health science/physical therapy 68.6%, health science/radiological technology 24.8%, health and sports science 26.2%, and international liberal arts 20.4%). The study included 192 male (35%) and 353 female students (64.3%). The participants’ response rate ranged from a minimum of 59.6% to a maximum of 100% (S2 Table).

Knowledge of public health topics total score and self-assessment total score

Kruskal–Wallis tests showed no significant differences among sexes [H(2) = 3.763, p = .152] or colleges in self-reported total knowledge scores among males [H(4) = 3.813, p = .432], females [H(4) = 8.175, p = .085], or total [H(4) = 2.186, p = .702] (Table 2A). Additionally, according to the one-way analysis of variance results, there were no significant differences between sexes [F(2, 494) = 0.001, p = .999] or colleges on the self-assessment total score among males [F(4, 163) = 0.353, p = .842], females [F(4, 320) = 1.940, p = .104], or total [F(4, 492) = 0.841, p = .500] (Table 2B). Pearson Chi-Square Tests indicated no significant differences among colleges in the three levels of knowledge (p = .122) or self-assessment (p = .635). However, a significant difference was observed among sexes in the three levels of self-assessment in the Health and Sports College (p = .011). Further pairwise comparison revealed significant differences in the “Poor” (p = .010) and “Fair” (p = .006) categories (Table 3).

Table 2. Total score rate of (A) students’ reported public health knowledge and (B) self-assessment.

	(A)Knowledge									(B)Self-assessment score
	Male			Female			Total			Male		Female		Total
	N	Median	95% CI	N	Median	95% CI	N	Median	95% CI	N	Mean±SD	N	Mean±SD	N	Mean±SD
Medicine	37	86.21	82.76–89.66	37	89.66	89.66–93.1	74	89.66	89.66–93.1	31	56.97±12.23	35	61.23±11.55	66	59.23±11.97
Nursing	7	89.66	86.21–100	145	86.21	86.21–89.66	153	86.21	86.21–89.66	7	61.53±11.13	132	56.01±13.39	140	56.16±13.34
Healthcare therapist	38	87.93	86.21–89.66	74	89.66	89.66–93.1	113	89.66	89.66–93.1	34	57.35±9.85	67	54.84±12.51	102	55.78±11.67
Health and sports	94	84.48	79.31–89.66	64	89.66	86.21–96.55	159	86.21	86.21–89.66	82	55.68±15.21	58	58.44±11.5	141	56.83±13.77
International liberal arts	16	79.31	79.31–93.1	33	89.66	86.21–96.55	50	86.21	79.31–89.66	14	57.17±16.85	33	55.09±14.4	48	55.93±14.93
Total	192	86.21	86.21–89.66	353	89.66	89.66–93.1	549	86.21	86.21–89.66	168	56.63±13.66	325	56.67±12.89	497	56.66±13.12

NOTE: The number of topics about which students reported having knowledge and their self-assessment knowledge level for the topic were calculated to percentage as score. N represents the number of students who answered all questions about self-assessment (S1 File).

Table 3. Three level of (A) students’ reported public health knowledge and (B) self-assessment.

		(A)Knowledge			(B)Self-assessment score
		Male(%)	Female(%)	Total(%)	Male(%)	Female(%)	Total(%)
Medicine	Good	7(9.5)	11(14.9)	18(24.3)	8(12.1)	12(18.2)	20(30.3)
	Fair	20(27)	22(29.7)	42(56.8)	16(24.2)	18(27.3)	34(51.5)
	Poor	10(13.5)	4(5.4)	14(18.9)	7(10.6)	5(7.6)	12(18.2)
	Total	37(50)	37(50)	74(100)	31(47)	35(53)	66(100)
Nursing	Good	2(1.3)	22(14.4)	24(15.7)	3(2.1)	32(22.9)	35(25)
	Fair	4(2.6)	68(44.4)	72(47.1)	3(2.1)	62(44.3)	65(46.4)
	Poor	1(0.7)	55(35.9)	57(37.3)	1(0.7)	38(27.1)	40(28.6)
	Total	7(4.6)	145(94.8)	153(100)	7(5)	132(94.3)	140(100)
Healthcare therapist	Good	5(4.4)	16(14.2)	21(18.6)	6(5.9)	13(12.7)	19(18.6)
	Fair	21(18.6)	36(31.9)	58(51.3)	24(23.5)	33(32.4)	58(56.9)
	Poor	12(10.6)	22(19.5)	34(30.1)	4(3.9)	21(20.6)	25(24.5)
	Total	38(33.6)	74(65.5)	113(100)	34(33.3)	67(65.7)	102(100)
Health and sports	Good	16(10.1)	18(11.3)	34(21.4)	22(15.6)	13(9.2)	35(24.8)
	Fair	40(25.2)	30(18.9)	71(44.7)	33(23.4)	37(26.2)	71(50.4)
	Poor	38(23.9)	16(10.1)	54(34)	27(19.1)	8(5.7)	35(24.8)
	Total	94(59.1)	64(40.3)	159(100)	82(58.2)	58(41.1)	141(100)
International liberal arts	Good	3(6)	8(16)	11(22)	3(6.3)	8(16.7)	12(25)
	Fair	4(8)	13(26)	18(36)	7(14.6)	15(31.3)	22(45.8)
	Poor	9(18)	12(24)	21(42)	4(8.3)	10(20.8)	14(29.2)
	Total	16(32)	33(66)	50(100)	14(29.2)	33(68.8)	48(100)
Total	Good	33(6)	75(13.7)	108(19.7)	42(8.5)	78(15.7)	121(24.3)
	Fair	89(16.2)	169(30.8)	261(47.5)	83(16.7)	165(33.2)	250(50.3)
	Poor	70(12.8)	109(19.9)	180(32.8)	43(8.7)	82(16.5)	126(25.4)
	Total	192(35)	353(64.3)	549(100)	168(33.8)	325(65.4)	497(100)

NOTE: Good: >75 percentile, Fair: 25–75 percentile, Poor: <25 percentile. The percentages represent the proportions relative to the total N of each college (S1 File).

Knowledge of public health topics and classroom involvement

There were 28 questions about whether students had knowledge of the topic and if they had learned it in class. More than 10% of the students were unfamiliar with 12 topics (two for Alcohol, Tobacco, and Other Drugs; nine for Growth, Development, and Sexual Health; and one for Personal and Community Health) of the 28 topics (Table 4A). More than 10% of the students responded that they did not learn about 11 topics (two for Alcohol, Tobacco, and Other Drugs; eight for Growth, Development, and Sexual Health; and one for Personal and Community Health) in class (Table 4B).

Table 4. Summary of students’ previous knowledge regarding public health topics: (A) Did not know about the topic; (B) Did not learn about the topic in classes.

	(A) Did not know about the topic				(B) Did not learn about it in classes
	Total (N = 545)	Sex (%)		p	Total (N = 545)	Sex (%)		P
		Male (N = 192)	Female (N = 353)			Male (N = 192)	Female (N = 353)
Nutrition and Physical Activity
Lifestyle-related diseases	46 (8.4)	19 (9.9)	27 (7.6)	.348	11 (2)	7 (3.6)	4 (1.1)	.044
Food poisoning	38 (7)	15 (7.8)	23 (6.5)	.570	21 (3.9)	10 (5.2)	11 (3.1)	.225
Allergic reaction	8 (1.5)	6 (3.1)	2 (0.6)	.018	7 (1.3)	5 (2.6)	2 (0.6)	.044
Alcohol, Tobacco, and Other Drugs
Health effect of smoking	1 (0.2)	1 (0.5)	0 (0)	NA	0 (0)	0 (0)	0 (0)	NA
Health hazard of passive smoking	10 (1.8)	1 (0.5)	9 (2.5)	.092	5 (0.9)	1 (0.5)	4 (1.1)	.475
Smoking effect on pregnancy	31 (5.7)	15 (7.8)	16 (4.5)	.114	21 (3.9)	8 (4.2)	13 (3.7)	.779
Dependence of smoking	6 (1.1)	1 (0.5)	5 (1.4)	.341	2 (0.4)	0 (0)	2 (0.6)
Health effect of e-cigarettes	197 (36.1)	63 (32.8)	134 (38)	.223	175 (32.1)	58 (30.2)	117 (33.1)	.470
Effect of alcohol consumption	9 (1.7)	4 (2.1)	5 (1.4)	.554	4 (0.7)	2 (1)	2 (0.6)	.531
Alcohol consumption effect on pregnancy	39 (7.2)	20 (10.4)	19 (5.4)	.030	24 (4.4)	11 (5.7)	13 (3.7)	.269
Mental/physical effect of mind-altering drugs	1 (0.2)	1 (0.5)	0 (0)	NA	1 (0.2)	1 (0.5)	0 (0)	NA
Alcohol, smoking and drug addiction	33 (6.1)	12 (6.3)	21 (5.9)	.888	17 (3.1)	7 (3.6)	10 (2.8)	.602
Addiction	117 (21.5)	45 (23.4)	72 (20.4)	.418	85 (15.6)	31 (16.1)	54 (15.3)	.805
Growth, Development and Sexual Health
Ovulation and menstruation	17 (3.1)	15 (7.8)	2 (0.6)	< .001	8 (1.5)	7 (3.6)	1 (0.3)	.002
Ejaculation	21 (3.9)	1 (0.5)	20 (5.7)	.003	10 (1.8)	1 (0.5)	9 (2.5)	.094
How to use condoms	129 (23.7)	15 (7.8)	114 (32.3)	< .001	86 (15.8)	10 (5.2)	76 (21.5)	< .001
Woman’s basal body temperature	190 (34.9)	103 (53.6)	87 (24.6)	< .001	139 (25.5)	76 (39.6)	63 (17.8)	< .001
Measurement of woman’s basal body temperature	274 (50.3)	128 (66.7)	146 (41.4)	< .001	217 (39.8)	106 (55.2)	111 (31.4)	< .001
Fertilization and pregnancy	7 (1.3)	3 (1.6)	4 (1.1)	.666	2 (0.4)	1 (0.5)	1 (0.3)	.659
Gestation period and childbirth	67 (12.3)	30 (15.6)	37 (10.5)	.085	24 (4.4)	15 (7.8)	9 (2.5)	.004
Public services related to pregnancy	96 (17.6)	44 (22.9)	52 (14.7)	.015	63 (11.6)	32 (16.7)	31 (8.8)	.006
Significance and importance of family planning	155 (28.4)	60 (31.3)	95 (26.9)	.293	118 (21.7)	43 (22.4)	75 (21.2)	.768
Abortion under Maternal Health Act in Japan	98 (18)	46 (24)	52 (14.7)	.008	67 (12.3)	35 (18.2)	32 (9.1)	.002
Sex and gender	131 (24)	33 (17.2)	98 (27.8)	.005	105 (19.3)	27 (14.1)	78 (22.1)	.022
LGBTQIA+	118 (21.7)	41 (21.4)	77 (21.8)	.862	96 (17.6)	33 (17.2)	63 (17.8)	.813
Personal and Community Health
Birth control pills and preventing sexually transmitted diseases	206 (37.8)	73 (38)	133 (37.7)	.940	163 (29.9)	58 (30.2)	105 (29.7)	.913
Prevention of sexually transmitted diseases	28 (5.1)	12 (6.3)	16 (4.5)	.383	16 (2.9)	8 (4.2)	8 (2.3)	.208
Vaccines	26 (4.8)	11 (5.7)	15 (4.2)	.428	21 (3.9)	9 (4.7)	12 (3.4)	.445

NOTE: Values in parenthesis represent percentage of valid N for each category. Results are based on two-sided tests for comparison between sexes. The p-value threshold for significance was adjusted for multiple comparisons using the Bonferroni correction. The threshold for statistical significance was set at p < .05 (S1 File).

Knowledge of specific public health items

Questions on whether they had knowledge of specific items, diseases, or terms like lifestyle-related diseases, contraception, LGBTQIA+ issues, pathogens causing infections, and transmission of infection showed that more than 75% of students reported that they had knowledge of at least one or more specific items (S3 Table).

Information sources for public health topics

We inquired about the sources of information for 29 topics and found that most students relied on teachers as their primary source of information. However, for 12 out of 29 topics, less than 75% of students chose teachers as their source of information. For nine out of 29 topics, more than 25% of the students relied on their parent(s) for information. While friends were not necessarily the primary source of information, more than 10% of students obtained information on six public health topics from friends. Additionally, the Internet was an important information source for all the topics. However, for six out of the 29 topics, more than 40% of the students selected the Internet as their primary source of information, with more than 50% selecting the Internet for two of the topics (Table 5).

Table 5. (A). Summary of sources of information regarding public health topics.

(B). Summary of sources of information regarding public health topics.

A
	Teacher(s) as information source				Parent(s) as information source
	Total (N = 545)	Sex (%)		p	Total (N = 545)	Sex (%)		p
		Male (N = 192)	Female (N = 353)			Male (N = 192)	Female (N = 353)
Nutrition and Physical Activity
Lifestyle-related diseases	467 (85.7)	161 (83.9)	306 (86.7)	.397	142 (26.1)	58 (30.2)	84 (23.8)	.100
Food poisoning	332 (60.9)	114 (59.4)	218 (61.8)	.596	230 (42.2)	76 (39.6)	154 (43.6)	.366
Allergic reaction	362 (66.4)	121 (63)	241 (68.3)	.357	262 (48.1)	86 (44.8)	176 (49.9)	.362
Alcohol, Tobacco, and Other Drugs
Health effect of smoking	491 (90.1)	174 (90.6)	317 (89.8)	.831	246 (45.1)	83 (43.2)	163 (46.2)	.491
Health hazard of passive smoking	481 (88.3)	166 (86.5)	315 (89.2)	.212	179 (32.8)	65 (33.9)	114 (32.3)	.761
Smoking effect on pregnancy	423 (77.6)	152 (79.2)	271 (76.8)	.658	112 (20.6)	35 (18.2)	77 (21.8)	.293
Dependence of smoking	470 (86.2)	168 (87.5)	302 (85.6)	.530	186 (34.1)	72 (37.5)	114 (32.3)	.222
Health effect of e-cigarettes	244 (44.8)	88 (45.8)	156 (44.2)	.685	103 (18.9)	39 (20.3)	64 (18.1)	.817
Effect of alcohol consumption	470 (86.2)	168 (87.5)	302 (85.6)	.637	207 (38)	78 (40.6)	129 (36.5)	.376
Alcohol consumption effect on pregnancy	435 (79.8)	157 (81.8)	278 (78.8)	.171	130 (23.9)	43 (22.4)	87 (24.6)	.636
Mental/physical effect of mind-altering drugs	501 (91.9)	173 (90.1)	328 (92.9)	.334	113 (20.7)	44 (22.9)	69 (19.5)	.338
Alcohol, smoking and drug addiction	480 (88.1)	169 (88)	311 (88.1)	.926	130 (23.9)	61 (31.8)	69 (19.5)	.001
Addiction	381 (69.9)	136 (70.8)	245 (69.4)	.705	75 (13.8)	30 (15.6)	45 (12.7)	.446
Growth, Development and Sexual Health
Ovulation and menstruation	475 (87.2)	166 (86.5)	309 (87.5)	.675	222 (40.7)	23 (12)	199 (56.4)	< .001
Ejaculation	453 (83.1)	159 (82.8)	294 (83.3)	.495	28 (5.1)	12 (6.3)	16 (4.5)	.417
How to use condoms	329 (60.4)	130 (67.7)	199 (56.4)	.854	9 (1.7)	3 (1.6)	6 (1.7)	.714
Woman’s basal body temperature	273 (50.1)	82 (42.7)	191 (54.1)	.611	70 (12.8)	7 (3.6)	63 (17.8)	< .001
Fertilization and pregnancy	488 (89.5)	172 (89.6)	316 (89.5)	.794	44 (8.1)	11 (5.7)	33 (9.3)	.131
Gestation period and childbirth	460 (84.4)	162 (84.4)	298 (84.4)	.760	93 (17.1)	18 (9.4)	75 (21.2)	.001
Public services related to pregnancy	351 (64.4)	121 (63)	230 (65.2)	.843	193 (35.4)	54 (28.1)	139 (39.4)	.020
Significance and importance of family planning	331 (60.7)	121 (63)	210 (59.5)	.193	90 (16.5)	31 (16.1)	59 (16.7)	.931
Contraception	427 (78.3)	154 (80.2)	273 (77.3)	.548	35 (6.4)	10 (5.2)	25 (7.1)	.381
Abortion under Maternal Health Act in Japan	386 (70.8)	135 (70.3)	251 (71.1)	.751	28 (5.1)	3 (1.6)	25 (7.1)	.006
Sex and gender	343 (62.9)	135 (70.3)	208 (58.9)	.085	14 (2.6)	5 (2.6)	9 (2.5)	.918
LGBTQIA+	299 (54.9)	115 (59.9)	184 (52.1)	.038	31 (5.7)	12 (6.3)	19 (5.4)	.645
Personal and Community Health
Prevention of sexually transmitted diseases	459 (84.2)	167 (87)	292 (82.7)	.081	31 (5.7)	9 (4.7)	22 (6.2)	.475
Pathogens that cause infections	430 (78.9)	152 (79.2)	278 (78.8)	.526	55 (10.1)	18 (9.4)	37 (10.5)	.745
Transmission of infection	409 (75)	151 (78.6)	258 (73.1)	.110	98 (18)	30 (15.6)	68 (19.3)	.307
Vaccines	438 (80.4)	151 (78.6)	287 (81.3)	.713	133 (24.4)	45 (23.4)	88 (24.9)	.785
B
	Friend(s) as information source				Internet as information source
	Total (N = 545)	Sex (%)		p	Total (N = 545)	Sex (%)		p
		Male (N = 192)	Female (N = 353)			Male (N = 192)	Female (N = 353)
Nutrition and Physical Activity
Lifestyle-related diseases	17 (3.1)	12 (6.3)	5 (1.4)	.002	208 (38.2)	83 (43.2)	125 (35.4)	.069
Food poisoning	25 (4.6)	10 (5.2)	15 (4.2)	.606	264 (48.4)	109 (56.8)	155 (43.9)	.004
Allergic reaction	61 (11.2)	24 (12.5)	37 (10.5)	.424	244 (44.8)	99 (51.6)	145 (41.1)	.010
Alcohol, Tobacco, and Other Drugs
Health effect of smoking	45 (8.3)	24 (12.5)	21 (5.9)	.008	233 (42.8)	98 (51)	135 (38.2)	.004
Health hazard of passive smoking	33 (6.1)	26 (13.5)	7 (2)	< .001	187 (34.3)	80 (41.7)	107 (30.3)	.009
Smoking effect on pregnancy	14 (2.6)	9 (4.7)	5 (1.4)	.022	152 (27.9)	62 (32.3)	90 (25.5)	.105
Dependence of smoking	45 (8.3)	29 (15.1)	16 (4.5)	< .001	173 (31.7)	78 (40.6)	95 (26.9)	.001
Health effect of e-cigarettes	39 (7.2)	24 (12.5)	15 (4.2)	.001	166 (30.5)	74 (38.5)	92 (26.1)	.009
Effect of alcohol consumption	49 (9)	26 (13.5)	23 (6.5)	.007	182 (33.4)	75 (39.1)	107 (30.3)	.043
Alcohol consumption effect on pregnancy	19 (3.5)	10 (5.2)	9 (2.5)	.096	146 (26.8)	54 (28.1)	92 (26.1)	.512
Mental/physical effect of mind-altering drugs	32 (5.9)	17 (8.9)	15 (4.2)	.028	223 (40.9)	94 (49)	129 (36.5)	.004
Alcohol, smoking and drug addiction	39 (7.2)	25 (13)	14 (4)	< .001	179 (32.8)	77 (40.1)	102 (28.9)	.008
Addiction	17 (3.1)	9 (4.7)	8 (2.3)	.141	136 (25)	54 (28.1)	82 (23.2)	.303
Growth, Development and Sexual Health
Ovulation and menstruation	58 (10.6)	20 (10.4)	38 (10.8)	.980	180 (33)	46 (24)	134 (38)	.002
Ejaculation	88 (16.1)	52 (27.1)	36 (10.2)	< .001	152 (27.9)	89 (46.4)	63 (17.8)	< .001
How to use condoms	100 (18.3)	60 (31.3)	40 (11.3)	< .001	167 (30.6)	94 (49)	73 (20.7)	< .001
Woman’s basal body temperature	13 (2.4)	12 (6.3)	1 (0.3)	< .001	102 (18.7)	32 (16.7)	70 (19.8)	.901
Fertilization and pregnancy	46 (8.4)	28 (14.6)	18 (5.1)	< .001	141 (25.9)	67 (34.9)	74 (21)	< .001
Gestation period and childbirth	19 (3.5)	11 (5.7)	8 (2.3)	.033	127 (23.3)	50 (26)	77 (21.8)	.233
Public services related to pregnancy	7 (1.3)	4 (2.1)	3 (0.8)	.198	105 (19.3)	43 (22.4)	62 (17.6)	.101
Significance and importance of family planning	10 (1.8)	7 (3.6)	3 (0.8)	.018	93 (17.1)	40 (20.8)	53 (15)	.063
Contraception	90 (16.5)	48 (25)	42 (11.9)	< .001	215 (39.4)	99 (51.6)	116 (32.9)	< .001
Abortion under Maternal Health Act in Japan	8 (1.5)	4 (2.1)	4 (1.1)	.356	132 (24.2)	48 (25)	84 (23.8)	.622
Sex and gender	50 (9.2)	24 (12.5)	26 (7.4)	.089	168 (30.8)	72 (37.5)	96 (27.2)	.051
LGBTQIA+	72 (13.2)	24 (12.5)	48 (13.6)	.763	277 (50.8)	102 (53.1)	175 (49.6)	.308
Personal and Community Health
Prevention of sexually transmitted diseases	37 (6.8)	26 (13.5)	11 (3.1)	< .001	167 (30.6)	79 (41.1)	88 (24.9)	< .001
Pathogens that cause infections	22 (4)	14 (7.3)	8 (2.3)	.004	197 (36.1)	82 (42.7)	115 (32.6)	.010
Transmission of infection	25 (4.6)	19 (9.9)	6 (1.7)	< .001	286 (52.5)	107 (55.7)	179 (50.7)	.225
Vaccines	21 (3.9)	16 (8.3)	5 (1.4)	< .001	213 (39.1)	90 (46.9)	123 (34.8)	.003

NOTE: Values in parenthesis represent the percentage of valid N for each category. Results are based on two-sided tests to compare between sex. The p-value threshold for significance was adjusted for multiple comparisons using the Bonferroni correction. The threshold for statistical significance was set at p < .05 (S1 File).

Self-assessment of knowledge level

The lowest level of self-assessed knowledge was 4.0 (95% CI, 4.0–5.0) for topics such as the health effects of e-cigarettes, women’s basal body temperature, and LGBTQIA+ issues. Moreover, the pinnacle of self-assessed knowledge reached 7.0 (95% CI, 7.0–8.0) on a scale with a maximum score of 10.0 for topics such as the health effects of smoking, the health hazards of passive smoking, smoking dependence, the mental and physical effects of mind-altering drugs, and ovulation and menstruation.

Comparison of previous knowledge and class involvement by sex

There was a significant difference between males and females in their previous knowledge of topics such as allergic reactions, alcohol consumption effects on pregnancy, ovulation and menstruation, ejaculation, how to use condoms, women’s basal body temperature, measurement of women’s basal body temperature, public services related to pregnancy, abortion under the Maternal Health Act in Japan, and sex and gender (Table 4A). Moreover, there were significant differences between males and females in reporting that they did not learn about certain topics in their classes, such as lifestyle-related disease, allergic reactions, ovulation and menstruation, how to use condoms, women’s basal body temperature, measurement of women’s basal body temperature, abortion under the Maternal Health Act in Japan, and sex and gender (Table 4B).

Comparison of sources of information by sex

Significantly more male students selected their teacher(s) as sources of information about LGBTQA+. However, significantly more female students selected their parent(s) as the source of information on the six topics. Furthermore, significantly more male students selected their friend(s) as a source of information than female students did for 20 out of the 29 topics. Additionally, significantly more male students reported the Internet as a source of information than female students for 16 out of 29 topics, while more female students reported the Internet as a source on one topic (Table 5).

Comparison of self-assessment by sex

The results of the Mann-Whitney U test demonstrated that male students reported significantly higher self-assessment scores on seven out of 29 topics, while female students reported significantly higher scores on five out of 29 topics (Table 6).

Table 6. Self-assessment of knowledge score comparison between sexes.

Key words	Sex			Male			Female			p
Nutrition and Physical Activity	Mann-Whitney U	Wilcoxon W	Z	N	Mean Rank	Rank Sum	N	Mean Rank	Rank Sum
Lifestyle-related diseases	34776	96904	.786	190	264.5	50249	352	275.3	96904	.432
Food poisoning	34866	97347	.566	192	267.9	51439	353	275.8	97347	.571
Allergic reaction	38638	100414	2.984	191	244.7	46739	351	286.1	100414	.003
Alcohol, Tobacco, and Other Drugs
Health effect of smoking	31622	94103	-1.314	192	284.8	54682	353	266.6	94103	.189
Health hazard of passive smoking	31031	93512	-1.653	192	287.9	55274	353	264.9	93512	.098
Smoking effect on pregnancy	38054	99830	2.525	192	249.3	47867	351	284.4	99830	.012
Dependence of smoking	29867	91995	-2.182	191	291.6	55701	352	261.4	91995	.029
Health effect of e-cigarettes	31109	93237	-1.449	191	285.1	54459	352	264.9	93237	.147
Effect of alcohol consumption	34666	97147	.555	191	267.5	51093	353	275.2	97147	.579
Alcohol consumption effect on pregnancy	35638	97414	1.339	190	258.9	49197	351	277.5	97414	.181
Mental/physical effect of mind-altering drugs	33824	95952	.019	192	272.3	52288	352	272.6	95952	.985
Alcohol, smoking and drug addiction	33391	95872	-.287	192	275.6	52913	353	271.6	95872	.774
Addiction	32058	92436	-.534	190	273.8	52017	347	266.4	92436	.593
Growth, Development and Sexual Health
Ovulation and menstruation	56749	119230	13.155	192	153.9	29556	353	337.8	119230	< .001
Ejaculation	16419	78900	-10.037	192	364.0	69886	353	223.5	78900	< .001
How to use condoms	16618	77344	-9.668	191	357.0	68186	348	222.3	77344	< .001
Measurement of woman’s basal body temperature	46965	108741	8.176	188	195.7	36790	351	309.8	108741	< .001
Fertilization and pregnancy	30672	92800	-1.611	190	286.1	54353	352	263.6	92800	.107
Pregnancy and childbirth	35016	97497	.860	190	264.2	50199	353	276.2	97497	.390
Public services related to pregnancy	36979	98755	2.008	191	253.4	48398	351	281.4	98755	.045
Significance and importance of family planning	35190	95568	1.306	190	257.3	48886	347	275.4	95568	.192
Contraception	27879	89655	-3.189	190	299.8	56957	351	255.4	89655	.001
Abortion under Maternal Health Act in Japan	36010	97085	1.669	190	255.0	48446	349	278.2	97085	.095
Sex and gender	29588	90663	-2.179	191	290.1	55408	349	259.8	90663	.029
LGBTQIA+	32848	93923	-.078	189	270.2	51068	349	269.1	93923	.938
Personal and Community Health
Prevention of sexually transmitted diseases	27177	88953	-3.597	190	303.5	57658	351	253.4	88953	< .001
Pathogens that cause infections	27178	88603	-3.467	189	301.2	56927	350	253.2	88603	< .001
Transmission of infection	30853	92629	-1.362	189	282.8	53441	351	263.9	92629	.173
Vaccines	33252	93630	.376	188	264.6	49750	347	269.8	93630	.707

NOTE: Mann–Whitney U test was used for comparison. The p-value threshold for significance was adjusted for multiple comparisons using the Bonferroni correction. The threshold for statistical significance was set at p < .05 (S1 File).

Discussion

This study aimed to assess the knowledge, sources of information, and self-assessment of essential public health topics among university students before beginning their healthcare education, as well as to evaluate differences in the choice of colleges that indicate their desired career path. To the best of our knowledge, there has been no prior investigation into the public health knowledge of healthcare university students before beginning their college education.

Although students reported being familiar of most of the health topics surveyed, there appeared to be a lack of knowledge in certain areas and reliance on skewed information sources, as detailed below.

Nutrition and physical activity

Ninety percent or more of the students affirmed their awareness of all three questions related to food poisoning and allergies, and reported their parent(s) and the Internet as sources of information. This finding suggests that education on public health knowledge related to daily life is likely to be provided at home. Although many students reported the internet as their source of information, it is important to note that the information available on the internet is not necessarily accurate. This could be particularly critical in situations related to food poisoning or allergies, where inaccurate information could have serious consequences.

Alcohol, tobacco, and other drugs

Over 75% of students indicated acquiring information concerning alcohol, tobacco, and other substances from both inside and outside the classroom, with the exception of the health impacts of e-cigarettes. The information sources included teachers, parents, and the Internet. However, many students were unaware of the health impact of e-cigarettes and addiction as a disease. They stated that they had never learned about these two topics in school. Although e-cigarettes are relatively new, their negative health effects have been reported in Japan and worldwide [30, 31]. The regulations for conventional cigarettes do not apply to e-cigarettes [32], leading to many advertisements targeting younger generations that present e-cigarettes as a less harmful alternative. We believe that education on this topic is essential in schools.

Growth, development, and sexual health

Nine out of the 12 topics had 10% or more students who reported having no knowledge, and 10% or more students reported that they had not learned about eight of these topics in class. In particular, fewer female students reported knowing how to use condoms, and fewer male students reported knowing about women’s basal temperatures. Furthermore, male students reported the Internet as a source of information on how to use condoms, and female students reported parents as a source of information on the basal temperature of women. In addition, many students reported not having learned about the public services available during pregnancy, the importance of family planning, biological and social concepts of sex, gender identity, and what LGBTQIA+ stands for in school. They reported friends as the information source for these topics. Despite LGBTQIA+ individuals having specific healthcare requirements, curricula do not address these requirements in depth [33]. It is important for future healthcare workers to receive adequate education regarding sexual health and related public services, as well as LGBTQIA+-related health information, to provide appropriate healthcare to diverse societies.

Personal and community health

Interestingly, many students reported knowing about infection pathways, vaccination, and essential information during the COVID-19 pandemic, with the Internet having a high percentage as a source of information. It is speculated that this awareness may be due to the COVID-19 pandemic. This finding is consistent with previous reports on knowledge and information sources regarding COVID-19 from around April 2020 in nursing [34], medicine [35], medical and health science [36], and undergraduate and postgraduate students [37]. These previous reports confirmed that students had adequate knowledge of COVID-19, and for the majority of students, the source of information was social media. Furthermore, many students reported that their sources of information about vaccination were their parents, compared with other topics. It can be speculated that vaccination, especially for minors, is a parental decision, even in the case of the COVID-19 vaccination. There have been reports that many people with vaccine hesitancy obtain information from the Internet and celebrities and tend to be suspicious of healthcare providers [38–41]. Therefore, education and communication are crucial [42, 43]. Environmental education studies on university freshmen have reported that the most important source of environmental education is the family, which provides long-term information and influences students’ knowledge and attitudes [44]. Thus, although accurate knowledge must be imparted to children in school, parents should also have access to accurate sources of information.

Overview

This study revealed skewed information sources, with more male students relying on the Internet and friends as information sources and a disparity between sexes in knowledge and self-assessment, especially regarding sexual health. Our results are consistent with a previous study on the source of sexual knowledge, which reported that female students’ ideal source of knowledge was school as a primary source, while male students preferred the Internet, friends, and parents in that order [13]. However, the disparity in class involvement for knowledge between the sexes on some sexual health topics in our study is notable. Although more female students reported that they did not learn about “how to use condoms” or “sex and gender” in class, more male students reported that they did not learn about topics related to women’s sexual health, such as “women’s basal body temperature” or “gestation period and childbirth”. We could speculate about several possibilities to explain this disparity. One possibility is actual educational differences based on sex, while the other is perceived differences. Historically, sexual education in Japan was conducted separately based on sex until recently [10, 45, 46]. Due to the long history of sexual education or lack thereof in Japan, students may consider topics not directly connected to their sex as irrelevant to them or not theirs to learn, thinking it is not their concern. With Japan ranking 120^th out of 156 countries in 2021 in the Global Gender Gap Index, it is crucial to educate not only students but also parents and educators that sexual health education is equally essential regardless of sex. Teaching sex education as health education, rather than merely teaching physiological differences and reproductive functions, is crucial to raising awareness of infection prevention, especially sexually transmitted infections, as well as enriching students’ lives to build a healthy society [47]. However, this survey also demonstrated that practical and essential knowledge of real life was somewhat limited, despite students’ knowledge of physiological differences.

This lack of knowledge is likely contributing to the increasing rates of sexually transmitted infections among young people within Japan and worldwide [3, 5]. With the rise of HIV/AIDS in the 1980s [48, 49], the importance of health education, including sex education, came to the forefront. However, political and social background differences have resulted in varying approaches to sexual health education worldwide, with some countries promoting abstinence-only education, lacking sexual health education altogether, or even discouraging its provision.

During the COVID-19 pandemic, educational lectures and practical training were moved to online formats, including healthcare education [50, 51]. While some countries and regions have accelerated medical students’ graduation and assigned them to work [52], the role of medical students during the pandemic remains controversial [53]. It is vital for the public, especially healthcare students, to have accurate public health information in this day and age. Thus, understanding these students’ knowledge gaps provides an opportunity to supplement and reinforce their understanding of critical health topics.

Limitations

There are some limitations to this study. First, while we surveyed seven college programs, we only conducted the study at one Japanese university. Thus, we cannot ignore the possibility that the results would be different if the study were conducted at a different university or country. Second, to the best of our knowledge, we were unable to find a validated public health knowledge questionnaire suitable for this study, and hence, we selected topics from the curriculum guidelines and current official textbooks ourselves. To provide anonymity, obtain honest answers, and give students the opportunity to gain insight into their own information gaps, we did not test the students; instead, we had them self-report their knowledge or lack thereof. Thus, there is a possibility of inaccurate reporting of their knowledge. Thirdly, we cannot rule out the possibility that students who answer surveys are not representative of the entire population. Finally, this study was conducted during the COVID-19 pandemic. Although the study provides a glimpse into students’ knowledge and attitudes in the age of the pandemic, the results may not be generalizable. Therefore, we recommend conducting further research on public health knowledge, both within and beyond Japan, to better understand the current state of health education and identify areas for improvement.

Implications

In Japan, health and sexual health education are not considered as enrollment requirements in any college, including health-related colleges, considering that they are not included in entrance exams. Therefore, students seldom receive health education, let alone enough to proceed with higher healthcare education. Additionally, Japanese medical students’ choice to attend medical school tends to be extrinsically rather than intrinsically motivated. Thus, they choose medicine because their grades are suitable for medical school admission. Although differences in knowledge on individual topics exist, no significant differences in total knowledge or total self-assessment scores were observed between colleges. Although further research is needed, we can speculate that medical students are not necessarily focusing on learning each topic related to public health towing to the reasons above, and they are not as interested in public health topics as is expected. The health topics in this study are particularly crucial topics derived from preschool curricula and textbooks through the end of high school in Japan and the United States. Hence, they are not expected to be taught in universities or healthcare-related colleges. In other words, the lack of knowledge at this point may not be supplemented before students become healthcare workers. To address this issue, we believe that supplemental education reinforcing public health knowledge at the beginning of university education is beneficial. However, conventional classroom education may not be effective as students may not consider all topics to be of concern. Instead, we suggest using student-centered learning methods, such as problem-based learning [54], project-based learning [55], and flipped classrooms [56], as additional supplemental basic public health knowledge education after enrollment. We believe that this approach will lay the foundation for future healthcare workers’ knowledge and, subsequently, enhance the essential knowledge and awareness required for a healthy society.

Conclusions

In this cross-sectional study, we identified a significant knowledge gap and an overreliance on misinformation sources concerning public health, particularly sexual health, which varied by gender. This finding emphasizes the need for early public health education and awareness-raising efforts in universities, emphasizing the equal importance of public health knowledge regardless of gender. Japanese education systems primarily focus on preparing students for university entrance exams, which has led to the neglect of health education as it is not a mandatory part of the exam or university admission requirements. Given the widespread misinformation present in today’s world, a policy for improving health education is essential not only to address the lack of accurate knowledge and prevent healthcare workers from acquiring erroneous information but also to raise awareness and decrease the gender gap in sexual health. In conclusion, introducing healthcare-related knowledge to university students, particularly as part of freshmen or healthcare-related schools’ curricula, would be beneficial for building a healthy society. This approach would run in parallel with professional training and contribute to creating awareness about public health issues, ultimately leading to a better-informed population and a healthier society.

Supporting information

S1 Table. List of specific knowledge questions regarding public health topics and answer choices (multiple answers).

(DOCX)

S2 Table. Inventory of questionnaire items, along with individual question response rates and corresponding keywords in tables.

(DOCX)

S3 Table. Comparison of students’ previous knowledge between sexes.

(DOCX)

S1 File. Questionnaire raw data.

(SAV)

Data Availability

All relevant data are within the paper and its Supporting Information files.

Funding Statement

Initials of the authors who received each award: MS Grant number: 18K13259 The full name of funder: JSPS KAKENHI URL of funder website: https://www.jsps.go.jp/english/e-grants/ The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.