Modifiable Determinants of Obesity in Native Hawaiian and Pacific Islander Youth

Abstract

In the United States, obesity continues to be a major public health concern. Obesity disproportionately affects Native Hawaiian and Other Pacific Islanders (NHOPI) who demonstrate alarming rates of obesity and its related chronic conditions. However, little is known about the causes of obesity for this group. Given the modest effects of individual-level obesity treatments, identifying the most impactful determinants that can be modified to prevent or reduce obesity in NHOPI youth is critical to the development of interventions that best meet the needs of this population. A systematic review was conducted in PubMed, with additional expert-recommended articles identified through the Hawai‘i Initiative for Childhood Obesity Research and Education (HICORE) research database, to evaluate the current body of research on modifiable determinants or correlates of obesity in NHOPI youth. Of an initial pool of 471 articles, 60 articles were read in full and 14 articles were selected for inclusion in the qualitative synthesis. Utilizing an ecological framework to identify gaps in the literature and suggest areas for future research, findings from this review indicate that early life and contextual factors—namely, infant-feeding mode, geographic location, and education—appear to play an important role in obesity in NHOPI youth. However, more research is needed, particularly pre-birth cohort studies evaluating the effects of prenatal and early life risk factors, studies on the sociocultural influences on obesity-related psychosocial factors and health behaviors, as well as the influence of environmental and policy-level variables.

Introduction

Obesity among children and adolescents has risen dramatically in the United States. While the prevalence of obesity in youth appears to have leveled off, prevalence remains high at 16.9%.¹ The epidemic proportions of obesity and its associated health problems have gained recognition as a major public health concern.^2,3 Obesity in youth is associated with physical and psychosocial risk factors such as high blood pressure, high cholesterol, abnormal glucose tolerance, low-self esteem, and stigmatization.^4–7 Moreover, obesity in youth tends to persist into adulthood.⁸ Obesity in adulthood is a major contributor to preventable morbidity and mortality, as it increases the risk of coronary heart disease, stroke, type 2 diabetes, and different cancers.⁹ It is projected that the costs attributable to overweight and obesity will account for 16-18% of total US health care expenditures by 2030.¹⁰

Obesity disproportionately affects racial and ethnic minorities, with a consistently higher prevalence in Hispanics and Blacks than in Caucasians.¹ While the National Health and Nutrition Health Examination Survey has not reported on Native Hawaiians and Other Pacific Islanders (NHOPI),¹¹ NHOPI constitute 1.2 million people and are the second fastest-growing racial/ethnic group in the United States, increasing 40% from 2000 to 2010.¹² While the NHOPI label encompasses at least 20 distinct groups share commonalities due to unique island cultures and history of colonization by the US government.¹³ NHOPI have the greatest representation in Hawai‘i and the US-Affiliated Pacific region (USAP).¹²

Until 2000, the US Census aggregated Native Hawaiians and Pacific Islanders with Asian Americans in a single racial group (Asian American and Pacific Islander [AAPI]).¹² This masked health disparities experienced by the NHOPI population and its subgroups and led to a paucity of disaggregated data on these heterogeneous groups.^14,15 Available evidence shows that NHOPI adults display alarming rates of obesity and related diseases. Compared to Caucasians, NHOPI are 30% more likely to be obese, 30% more likely to be diagnosed with cancer, twice as likely to be diagnosed with diabetes, and three times more likely to be diagnosed with coronary heart disease.¹⁶ The Children's Healthy Living Program estimates the overall prevalence of overweight or obesity (OWOB) in Hawai‘i and the USAP to be 21% in 2 year-olds (y/o) and 39% in 8 y/o, which exceeds corresponding national averages of 15.6% for 2–5 y/o and 26% for 6–11 y/o.^1,17 Additionally, NHOPI adolescents in Hawai‘i were found to have OWOB rates 10% higher than other ethnic groups.¹⁸

Given the rapid growth of the NHOPI population, the relative paucity of data specific to this group, the disproportionate burden of obesity and its associated diseases in adults, and high prevalence of OWOB in youth, it is imperative that evidence-based obesity interventions be developed that best meet the needs of this group. In recent years, the traditional focus on the etiology of obesity as an energy-balance equation has been expanded to consider a broader ecological context.¹⁹ In public health, ecological models account for people's interactions with their physical and sociocultural surroundings.²⁰ In contrast to traditional behavior change paradigms, ecological models are set apart by their inclusion of environmental and policy variables.^21,22 Instead of a sole focus on the influence of a narrow range of psychosocial variables on behavior, these models incorporate a wide range of influences at multiple levels of one's environment.²² These levels include the intrapersonal (biological, psychological), interpersonal (social, cultural), organizational, community, physical environment, and policy.²² Ecological models are thought to provide comprehensive frameworks for understanding multiple, interacting determinants of health behaviors and are well suited for multifactorial behaviors.²² While eating and physical activity are fundamental behaviors governing energy balance, they are mediated by a range of influences.²³ In light of this, researchers have called for more complex, multilevel approaches to understanding and preventing childhood obesity.^23,24

Given the modest long-term effects of individual-level obesity treatments in adults, efforts should prioritize reducing the incidence of OWOB among youth.¹⁹ To inform the development of a comprehensive intervention targeting different levels of influence, an evidence base of the key determinants of OWOB in NHOPI youth must be developed. The purpose of this study is to systematically assess the existing body of research on modifiable determinants or correlates (able to be changed with intervention, eg, parental determinants, diet, sleep, etc.) of OWOB in NHOPI youth, using the ecological model as a framework to identify gaps in the literature and suggest areas for future research.²⁵ To the best of the authors' knowledge, no review of this nature has been conducted to date.

Methods

A literature review was conducted in PubMed of original articles published between January 2000 and February 2015. Additionally, expert-recommended articles were identified through the Hawai‘i Initiative for Childhood Obesity Research and Education's (HICORE) research database. Search terms were “obesity” and “Pacific Islander” or “Hawaiian.” When possible, results were filtered by age category (child: birth–18 years), otherwise “child” and “adolescent” were included as additional search terms. Inclusion criteria are listed in Table 1. There was no restriction on study design due to the relative paucity of research on this topic. Only studies with modifiable determinants or correlates were considered, as results of this review are intended to guide intervention development.

Table 1.

Inclusion criteria for the selection of articles on modifiable determinants or correlates of obesity in Native Hawaiian and Other Pacific Islander (NHOPI) youth

The article was from the U.S. or U.S. Affiliated Pacific region NHOPI was the primary study population If NHOPI was not the primary study population, or if Asian American and Pacific Islander (AAPI) were, only articles with a disaggregated sub-analysis of NHOPI were considered due to the tendency for AAPI data to mask disparities in its subpopulations14,15,26 The study sample's age ranged from birth–18 years Articles on mothers or caregivers were considered if obesity-related knowledge, attitudes, or behaviors in infancy or childhood were identified Overweight or obesity (OWOB) was a primary outcome variable At least one modifiable determinant or correlate of OWOB was assessed

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses Checklist and Flow Diagram were used to guide the search process.²⁷ The search yielded an initial pool of 471 articles, 324 from PubMed and 147 from the HICORE database. After eliminating duplicates, the remaining articles were screened by title and abstract for relevance, resulting in the removal of 406 articles that did not meet inclusion criteria. Sixty articles were read in full to determine eligibility. Of these, 46 were excluded for reasons (see Figure 1), such as not including an OWOB outcome, not analyzing the relationship between OWOB and a determinant or correlate, or not disaggregating NHOPI from AAPI data. Through this process, 14 articles were selected for inclusion in the qualitative synthesis. Two of these articles were featured in a 2011 special issue of the Hawai‘i Medical Journal on obesity in youth in Hawai‘i.^28,29 Additionally, two articles represent the same study.^30,31 Data were extracted from all reviewed articles (Table 2). Inter-rater reliability with a PhD-level content expert on a subset of articles (n=2) revealed 95% agreement.

Figure 1.

Flow chart of the systematic literature review process of articles on the determinants or correlates of obesity in Native Hawaiian and Other Pacific Islander (NHOPI) youth

Table 2.

Qualitative review of research addressing determinants or correlates of obesity in Native Hawaiian and Other Pacific Islander (NHOPI) youth

Citation	Study population	Study Design	Predictors/correlates	Outcome variable measure	Results
Prenatal
CDC, 2011	Washington 28,671 Infant-mother pairs 2,442 NHOPI & 26,229 Asian pairs	Cross-sectional	Maternal characteristics: Pre-pregnancy height & weight Initiation of prenatal care Maternal age Smoking during pregnancy	Infant characteristics: Birth weight (BW) Length of gestation	Infants born to NHOPI mothers significantly more likely than Asian counterparts to be born preterm (P<.001), at high BW (P<.001), or to have received late/no prenatal care (P<.001). NHOPI mothers significantly more likely than Asian mothers to be OWOB (P<.001) before pregnancy, to smoke during pregnancy (P<.001), or to be adolescents (P<.001).
Utz, et al, 2012	Utah 229,598 Adolescent (16 or 17y/o) - mother pairs 2,743 NHOPI, 987 Asian, & 225,868 Non-Hispanic white pairs	Retrospective	Maternal exposure to prenatal care (initiation & utilization) Potential covariates: Adolescent variables (birth weight, exact age at BMI measurement, birth year, gender) Maternal variables (educational attainment, pre-pregnancy BMI, gestational weight gain, smoking / drinking behaviors)	Overweight or obesity (OWOB) in adolescence (BMI)	Adolescents of others who received early (first trimester initiation) or adequate (defined by Kotelchuck Index) prenatal care were significantly less likely to be OWOB (data not shown). NHOPI mothers less likely to receive adequate prenatal care, largely driven by late initiation (P<.05). NHOPI demonstrated the largest protective effect of early prenatal care on the risk of adolescent obesity (P<.001). The effect remained after controlling for maternal education (P<.05), but became non-significant (P=.1) after controlling for pre-pregnancy BMI.
Infancy (birth – 2 y/o)
Hawley, et al, 2014	American Samoa 795 Infants Ages 0–15 mo.	Longitudinal	Feeding mode at 4 mo. (+/− 2 mo.): Breastfed Formula fed Mixed-fed (breast milk, formula, or solid foods)	OWOB at 15 mo. (BMI z-score) Rapid growth (RG) (Conditional gain >.67 z-scores)	Formula-fed infants gained weight & length faster than breastfed infants (P<.05). Formula-fed boys were significantly more likely to be obese at 15 mo. than breastfed boys (P<.01). There were no significant differences in girls at 15 mo., but OWOB was greater in the mixed-fed group. There was a significant difference in RG by feeding mode among boys (27% RG in formula-fed, 17% breastfed, & 6.4% mixed fed) (P<.01), but not girls.
Novotny, et al, 2007	Common - wealth of the Northern Marianas Islands (CNMI) 420 children participating in WIC Ages 6 mo.–10 y/o 54 native Chamorro, 8 native Carolinian, 69 Filipino, & majority mixed ethnicity or of other ethnicities	Cross-sectional	Primary caregiver's report of past breast feeding	OWOB in childhood (BMI)	Any breastfeeding was negatively associated with BMI (after adjusting for age, sex, BW, & mother's years of education) (P=.043). The association of BMI w/ exclusive breastfeeding & duration of breastfeeding were not significant.
Okihiro, et al, 2012	Hawai‘i 389 children Ages 4–5 y/o 66% Native Hawaiian (NH), 21.6% Samoan, & 12.3% Filipino	Retrospective	Growth acceleration during first 2 years of life (consecutive time intervals: 2 days–5 mo., 6–11 mo., & 12–23 mo.) Severe RG (increase in weight-for-length z-score of ?1.0 SD over an age interval) Moderate RG (increase in weight-for-length z-score of ?.67 SD, but <1.0 SD over an age interval)	OWOB at pre-kindergarten (PreK) (BMI)	Severe RG from 12–23 mo. was strongly associated w/ PreK obesity (OR 4.36, 95% CI 1.85–10.27), w/ 48% of these children obese at PreK, compared to 16.7% of children w/ moderate RG & 19.3% w/out RG.
Childhood (3 – 10 y/o)
Pobutsky, et al, 2013	Hawai‘i 12,823 children Ages 4–5 y/o	Cross-sectional	School Complexes	OWOB (BMI)	28.6% of children were overweight or obese (14.4% &14.2%, respectively). Proportions of OWOB were persistently higher (32.5%+) in certain school complexes on O‘ahu (Farrington, Kahuku, Waialua, & Waipahu), as well as some rural & neighbor island school complexes (Lana‘i & Lahainaluna)
Stark, et al, 2011	Hawai‘i 554 children Ages 2–10 y/o 42.6% NH/ part-NH, 6.9% Pacific Islander (PI), 18.8% Asian/part- Asian, 2.7% Hispanic, 18.4% Filipino, 7.6% White, & 5.8% Hispanics, Black & Other	Cross-sectional	Socio-economic status (SES) (Medicaid vs non-Medicaid) Place of residence	OWOB (BMI)	Boys had a higher incidence of OWOB (54%) than girls (46%). No association between SES & OWOB. PI had highest incidence of OWOB (40%) followed by NH/part-NH (19%) & Filipinos (19%). PI 3.6 times more likely to be OWOB. There was a significant relationship between OWOB & place of residence (P=.008). Children from West O‘ahu, Honolulu, & Central O‘ahu/North Shore areas were 2-3 times more likely to be OWOB compared to those from the Windward side.
Novotny, et al, 2013	Hawai‘i 4,608 children Ages 5–8 y/o 13.6% White, 9.4% Asian, 9.9% Filipino, 7.1% NH, 15.2% NH-Asian mixed, 1.9% Samoan, 33.1% other mixed (Incl. African American, American Indian/Aleutian/Eskimos, or other PI), & 9.8% Other	Cross-sectional	Neighborhood education level A subsample (n=2,169) had Vital Records data on: Maternal education level Maternal age	OWOB (BMI z-score)	All children, except Asians, significantly more likely to be OWOB compared to Whites (P<.05). Excess risk varied by ethnic group (Samoan & NH had the highest; OR = 9.4, OR = 2.5, respectively). There was a significant association between ethnic group & neighborhood education level (P<.001), which held after adjusting for age & sex (data not shown). Older maternal age groups (P<.04) & higher maternal education levels (P=.001) were associated w/ lower BMI among children.
Brown, et al, 2011	Hawai‘i 125 kindergarten (K) & third grade students K: mean age 5.6 y/o Third grade: Mean age 8.7 y/o 48.8% NH, 57.8% non-NH	Cross-sectional	Cohort (K or third grade) Sex Hawaiian ancestry Parental educational attainment Household	OWOB (BMI z-score & other adiposity measures eg, waist circumference, abdominal circumference, etc.)	BMI z-scores were significantly higher in third grade male NH children (P<.01). There was no significant ethnic difference in adiposity measures in kindergarteners. Among third grade girls, father's educational attainment was significantly & inversely related to adiposity measures (P<.1). Hawaiian ancestry & income was not significantly related to adiposity measures.
Bruss, et al, 2003 & Bruss, et al, 2005	CNMI 32 primary caregivers of children (ages 6–10 y/o)	Observational	Sociocultural & familial factors	Child feeding practices Perceptions of weight normalcy	Themes: Caregivers, esp. mothers, demonstrate inner dissonance when child-feeding practices conflict w/ cultural values related to food, identify challenges posed by the community as a barrier to healthful eating habits for their children. Cultural differences among ethnic groups regarding children's weight status. Intergenerational conflict related to child feeding between mothers & grandmothers. Both mothers & fathers report intra-family conflict related to child feeding. Parents report avoiding emotional conflicts related to child feeding.
DeRenne, et al, 2008	Hawai‘i 68 K- sixth grade students, enrolled in the A+ afterschool program at two schools About 75% NH	Quasi-experiment	Primary objective: assess feasibility of incorporating physical activity (PA) into an afterschool program Secondary objective: compare effectiveness of two intervention programs: - School A: model curriculum led by trained after school leaders - School B: structured activity program designed & taught by PE teacher	Anthropometric measures (stature, weight, skin fold thickness to determine BMI & estimate body fat) Health-related physical fitness, knowledge & attitudes on PA	After 12 weeks, children from both groups had a mean decrease of 1.2mm in the sum of skinfolds (P<.05) & a significant increase in mean distance covered in the 3-min walk-run test (P<.001). Students in School B had better scores on all variables & significantly lowered BMI (P<.05), did more sit-ups (P<.001), & covered longer distances on the walk-run test (P<.05) than School A.
Adolescence (12 – 18 y/o)
Teranishi, et al, 2011	Hawai‘i 874 children & adolescents Ages 10–17 y/o Over 33% multiracial, 25%White only, 20% Asian only, 20% NHOPI	Cross-sectional	Child's health status (reported excellent-to-poor by parents) Potential covariates: Demographics (Parental education, federal poverty level, insurance type, primary household language, parent nativity)	OWOB (BMI)	Children reported to be in poorer overall health were 2.92 times more likely to be OWOB than those in better health (after accounting for age, race, gender, parental education). Compared to Asian children, NHOPI & multiracial children were 3.04 & 2.31 times as likely to be OWOB. Boys were 1.94 times more likely than girls to be OWOB. Children whose parents' highest level of education was <12 years were 4.40 times more likely to be OWOB than children w/ at least one parent w/ >12 years of education.
LeonGuerrero, et al, 2004	Guam 643 middle & 590 high school students 54% & 53% Chamorro, 32% & 31% Filipino, 6% & 3% Micronesian Islander, 5% Asian, 5% Other ethnicity	Cross-sectional	Demographic characteristics Drug use behaviors	OWOB (BMI)	Adolescent males more likely to be OWOB than adolescent females (P<.01). Filipino adolescents had significantly lower BMI than all other ethnic groups (P<.01). There was a significant difference in percent of OWOB in Chamorro adolescent girls (31.01%) vs Filipino adolescent girls (11.42%) (P<.0001). OWOB adolescents significantly more likely to try marijuana (P<.01). & cocaine (P<.05) than “healthy weight” counterparts. OWOB adolescent girls significantly more likely to smoke cigarettes (30%) than “healthy weight” counterparts (P<.05).

^*NHOPI=Native Hawaiian or Pacific Islander; NH = Native Hawaiian; OWOB=overweight or obese; BMI = body mass index; BW = birth weight; mo. = months; y/o = years old; wks = weeks; w/ = with; & = and

Results

A summary of the results is provided in Figure 2. Identified determinants or correlates are presented from left to right, based on the order they appear in this review. Arrows are used to highlight determinants that have demonstrated significant impact on OWOB in multiple studies and those that have demonstrated significance in just one study.

Figure 2.

Modifiable determinants or correlates that have shown to impact overweight or obesity (OWOB) in Native Hawaiian and Other Pacific Islander youth

Prenatal

Two studies assessed prenatal determinants or correlates of OWOB.^32,33 In both, infants born to NHOPI mothers were significantly more likely to be high birth weight than other ethnic groups (Asian and/or Non-Hispanic White).^32,33 While one study found that NHOPI infants were also more likely to be born at low birth weight than other groups,³³ the other found they were more likely to be born pre-term.³² Both found NHOPI mothers to have significantly higher pre-pregnancy obesity prevalence and lower likelihood of receiving early prenatal care (first trimester initiation) than other ethnic groups.^32,33

Only Utz and colleagues assessed the impact of one of these prenatal determinants (maternal exposure to prenatal care) on subsequent OWOB in youth.³³ This study revealed a large protective effect of mothers receiving early prenatal care on the risk of adolescent obesity in the NHOPI group. This effect was smaller, but still significant for Whites and there was no effect for Asians. After controlling for maternal education, this effect remained for the NHOPI group; however, it became insignificant (P =.1) after controlling for maternal pre-pregnancy Body Mass Index (BMI).

Infancy

Three studies assessed determinants or correlates present in infancy.^34–36 Two studied the relationship between breastfeeding and OWOB.^34,35 In a sample of children from the Commonwealth of the Northern Mariana Islands (CNMI), Novotny and colleagues found that those who had been breastfed had significantly lower BMIs than those who had not.³⁴ However, there were no significant associations between BMI and breastfeeding exclusivity or duration. In a sample of Samoan infants, Hawley and colleagues found that formula-fed boys were significantly more likely to be obese at 15 months than breastfed boys.³⁵ While no significant differences were seen in girls, OWOB prevalence was highest in the mixed-fed group. Furthermore, there was a significant difference in rapid growth (RG) by feeding mode, with formula-fed boys demonstrating greater RG than breast-fed or mixed-fed groups. However, no significant differences were seen in girls.³⁵

Hawley and colleagues found that 21.8% of Samoan infants demonstrated RG over the first 12 months of life, with weight gain occurring almost exclusively during the first four months.³⁵ While this study did not evaluate the relationship between RG and subsequent obesity in infancy, Okihiro and colleagues found a strong association between severe RG from 12–23 months and obesity in prekindergarten in a predominantly Hawaiian and Samoan sample.³⁶ Of the infants who demonstrated severe RG from 12–23 months, 48% were obese by prekindergarten.

Childhood

The majority of studies assessed determinants or correlates of OWOB in childhood. Two considered the relationship between geographic location and OWOB in Hawai‘i.^29,37 Pobutsky and colleagues evaluated 4–5 y/o children entering the public school system,³⁷ while Stark and colleagues assessed 2–10 y/o from a Health Maintenance Organization.²⁹ The O‘ahu school complexes identified by Pobutsky, et al, as having higher proportions of OWOB corresponded with areas where Stark, et al, had reported 2–3 times greater childhood OWOB than in a referent area.^29,37 While Pobutsky and colleagues did not analyze the relationship between geographic location and OWOB by ethnicity, they note that the school complexes with the highest proportions of OWOB were in communities with higher proportions of NHOPI and Filipinos, as well as greater socioeconomic disparities.³⁷

Two studies considered the relationship between education and OWOB.^38,39 Novotny and colleagues assessed a sample of 5–8 y/o children from Kaiser Permanente,³⁸ while Brown and colleagues studied kindergarten and third graders from Hawai‘i Island.³⁹ Brown and colleagues found that adiposity in third grade girls was inversely related to father's educational attainment. However, the same relationship did not exist for mothers and was not seen in boys.³⁹ Novotny and colleagues found a significant interaction between OWOB and neighborhood education level by ethnic group. Among Samoan, Native Hawaiian, mixed, and other children, those who lived in neighborhoods with the lowest education level (high school or less) were the most likely to be OWOB. This contrasted with children of other ethnic groups, in that those who lived in neighborhoods with the second lowest education level (some college) were the most likely to be OWOB.³⁸

One study, represented by two articles, explored sociocultural and familial factors related to child-feeding practices and perceptions of weight normalcy among caregivers of 6–10 y/o in CNMI.^30,31 Caregivers identified how sociocultural values (eg, perception of food as a demonstration of love), family expectations (eg, grandparents' negative perception of thinness, grandparents undermining child-feeding practices, or parental conflicts over child-feeding), and traditional dietary beliefs and attitudes (eg, perception that being thin is unhealthy) were at odds with their knowledge of food and disease. Furthermore, caregivers identified limited awareness of disease and its relationship to diet as a stress factor when attempting to establish appropriate feeding-practices. This study also found perceptions of weight normalcy to vary between Pacific Islanders and Filipinos, in that Filipinos perceived being overweight as less acceptable than Micronesians, who associated thinness with illness.

One study evaluated the effectiveness of incorporating physical activity into an afterschool program on children's anthropometric measures and physical fitness in a predominantly Hawaiian sample.⁴⁰ The effectiveness of the two programs was compared: the first included a model curriculum led by trained after-school teachers and the second was a structured activity program designed and taught by a physical education teacher. After implementing these enhanced programs for 12 weeks, students had a significant mean decrease in the sum of skinfolds and an increase in mean distance covered in a 3-minute walk-run test. However, children in the program designed and taught by a physical education teacher experienced better outcomes for all variables, including significant differences in BMI, sit-ups, and the 3-min walk-run test, than children in the model curriculum program.

Adolescence

Two studies assessed OWOB determinants or correlates in adolescence.^28,41 Teranishi and colleagues evaluated adolescents' reported health status and demographics in relation to BMI in a sample of 10–17 y/o in Hawai‘i.²⁸ They found that adolescents reported by their parents to be in poorer overall health were 2.92 times more likely to be OWOB than those reported to be in better health and that NHOPI children were 3.04 times as likely to be OWOB. Furthermore, children whose parents' had less education (< 12 years) were 4.40 times more likely to be OWOB compared to children of at least one parent with more education (> 12 years).

LeonGuerrero and Workman studied demographic characteristics and health risk behaviors in relation to BMI in adolescents of Chamorro, Filipino, and other ethnic backgrounds (Micronesian, Asian, or other) in Guam.⁴¹ They found Chamorro or “other” ethnicity adolescents demonstrated significantly higher BMIs than Filipino adolescents, which was most pronounced in females. Additionally, OWOB adolescents were more likely to engage in high-risk behaviors, such as tobacco and drug use, and were significantly more likely to try marijuana and cocaine than “healthy weight” adolescents. In particular, OWOB adolescent girls were significantly more likely to smoke cigarettes than their “healthy weight” counterparts. While the dietary intake, physical activity, and sedentary behavior of this sample were deemed suboptimal, the relationship between these behaviors and OWOB was not analyzed.⁴¹

Discussion

The determinants identified by this review can be categorized as prenatal/early life, contextual, or behavioral factors. While all determinants demonstrated significance, there was a larger evidence-base for the impact of breastfeeding, geographic location, and education. From an ecological standpoint, the levels of influence lacking from this review include: the intrapersonal, obesity-related psychosocial variables and behaviors; the interpersonal, sociocultural environment; and, aside from the community-level factors of geographic location or neighborhood education level; the broader environmental and policy variables.

Findings from this review regarding the impact of breastfeeding are consistent with past research confirming a small but significant protective effect of breastfeeding against childhood obesity.^42,43 While rates of breastfeeding in American Samoa and CNMI meet or exceed national averages,^34,35,44 NHOPI in Hawai‘i are less likely to initiate breastfeeding than other ethnic groups and, if initiated, are more likely to breastfeed for less than 8 weeks.⁴⁵ Research on other U.S. ethnic groups have revealed differences in prenatal/early life risk factors for childhood obesity,^46,47 which may partially account for the presence of ethnic disparities by preschool.¹ While some of these risk factors have been identified by this review, more research is needed to determine their impact in the NHOPI population, ideally through pre-birth prospective cohort studies.

The associations between geographic location and education with OWOB were supported by multiple studies reviewed. Though these contextual factors could reflect a number of confounding variables (eg, rural vs urban place of residence), it is possible that both observed associations are indicative of socioeconomic status (SES). Ethnic variation has been noted in the relationship between SES and childhood obesity,⁴⁸ and a difference between NHOPI and other ethnic groups, regarding susceptibility to childhood obesity by neighborhood education level (used as a proxy for SES), was noted.³⁸ Future efforts should attempt to verify the SES gradients in obesity for NHOPI youth to identify which groups(s) may benefit most from intervention. While one study identified community-level influences (neighborhood education level),³⁸ more research on the environmental and policy-level influences on obesity in this population are needed.

The direct effects of healthy eating and physical activity on weight status are well established. However, there was a surprising lack of studies focusing on these central health behaviors in NHOPI youth. Furthermore, with the exception of one study,^30,31 the psychosocial precursors (eg, knowledge, attitudes, intention, and self-efficacy) of these behaviors and the socio-cultural influences on these precursors were largely absent from this review. Given that sociocultural environments of other US ethnic groups appear to support obesity development,⁴⁹ more research assessing the potential obesogenic influence of the sociocultural environment of NHOPI on its youth is needed. This approach will promote the development of culturally based obesity interventions, which have demonstrated success in the Native Hawaiian adult population and suggest promise for similar, youth-oriented programs.^50,51

In light of the number of articles identified by this review, the conclusions that can be drawn at this point are preliminary. This review is limited by publication bias, in that all studies reviewed were published in peer-reviewed journals; thus, more likely to demonstrate statistically significant results. While the inclusion of articles published from 2000 to 2015 was based on the 2000 Census revision that disaggregated AAPI data, studies published prior to 2000 that may have otherwise qualified for inclusion were not examined. Furthermore, the search terms and inclusion criteria may have excluded studies addressing obesity in NHOPI youth, but lacking a deterministic approach (eg, those with an intervention based approach). Despite these limitations, these findings are instrumental, as they provide a systematic assessment of the current body of knowledge on this topic and suggest areas for future research.

Conclusion

Results from this review suggest that prenatal/early life and contextual factors play an important role in OWOB in NHOPI youth. This highlights the value of interventions addressing prenatal/early life risk factors, namely infant-feeding mode, as well as efforts to ameliorate systemic socioeconomic disparities experienced by NHOPI. It is clear that more research is needed to identify the most salient determinants of obesity in NHOPI youth, with particular focus on psychosocial precursors, health behaviors, sociocultural influences, and environmental/policy-level factors. In taking a deterministic approach to identifying the most salient modifiable causes of obesity, interventions grounded in an understanding of the multiple interacting influences of obesity can be developed to maximize the impact on obesity prevention in NHOPI youth.

Biography

Katherine W. Braden

Katherine Braden holds a Bachelor of Arts degree in Psychology with a minor in Sociology, magna cum laude, from the University of San Diego. She is a Master of Public Health student with a specialization in Social and Behavioral Health Sciences, graduating from the University of Hawai‘i's Office of Public Health Studies in May 2016. She works as a Graduate Research Assistant for the Hawai‘i State Department of Health's Healthy Hawai‘i Initiative Evaluation Team, assisting with the evaluation of statewide physical activity and nutrition projects implemented in the community setting. Her research and professional interests include physical activity and nutrition, childhood obesity, socioeconomic determinants of health and health equity, public health evaluation, and public health workforce development. Katherine is a member of the Delta Omega National Public Health Honor Society.

Her winning manuscript, Modifiable Determinants of Obesity in Native Hawaiian and Pacific Islander Youth, is a systematic literature review that assesses the existing body of research on modifiable determinants and correlates of obesity in Native Hawaiian and Other Pacific Islander (NHOPI) youth. Mentored by faculty advisor Claudio Nigg PhD, this research reviewed articles published between 2000 and 2015 in PubMed, with additional expert recommended articles identified through the Hawaii Initiative for Childhood Obesity Research and Education (HICORE) research database. Of an initial pool of 471 articles, 60 articles were read in full and 14 articles were selected for inclusion in the qualitative synthesis. Utilizing an ecological model as a framework to identify gaps in the literature and suggest areas for future research, findings from this review indicate that early life and contextual factors—namely, infant feeding mode, geographic location, and education—appear to play an important role in obesity in NHOPI. However, more research is needed, particularly pre-birth cohort studies evaluating the effects of prenatal and early life risk factors, studies on the sociocultural influences on obesity-related psychosocial factors and health behaviors, as well as the influence of environmental and policy-level variables.

Conflict of Interest

None of the authors identify a conflict of interest.