Global prevalence and incidence of precocious puberty: a systematic review and meta-analysis

Abstract

Background

The significant rise in precocious puberty rates over recent decades has adversely impacted children’s health, spurring numerous epidemiological studies. However, prevalence and incidence estimates vary widely across regions and lack a comprehensive global perspective. Therefore, we estimated the global prevalence and incidence of precocious puberty among children.

Methods

We comprehensively searched PubMed, Embase, and Web of Science from inception to February 2024 for articles reporting the prevalence or incidence of precocious puberty. For studies based on cross-sectional surveys, we used a random-effects model to estimate the pooled prevalence and 95% confidence interval (CI) of precocious puberty in girls and boys. The 95% CI was calculated using the inverse-variance method, which accounts for both within-study and between-study variability. Subgroup analyses considered socioeconomic and individual characteristics. For studies based on medical registration data, we described the results individually due to significant heterogeneity, rather than pooling the data.

Results

Of 8737 articles identified, 27 were included. Survey-based studies showed pooled prevalence estimates of 7.87% (95% CI: 5.90%-9.84%) for girls and 3.98% (95% CI: 2.70%-5.25%) for boys. European and the United States studies were generally conducted earlier than those in Asia. Older and obese children exhibited significantly higher prevalence. Registry-based studies reported overall prevalence ranging from 37 to 935.1 per 100,000 girls and from 0.46 to 37.4 per 100,000 boys, with incidence ranging from 1.123 to 489.3 per 100,000 girls and from 0.096 to 22.4 per 100,000 boys.

Conclusions

This study synthesized the global prevalence and incidence of precocious puberty, offering valuable insights for public health awareness and policy-making. Further research is needed to enhance understanding of the condition and to guide targeted interventions.

Trial registration

PROSPERO number: CRD42024508384.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-025-25723-4.

Background

Puberty marks a critical transition from childhood to adulthood, characterized by the body’s progressive sexual maturation, attainment of full reproductive capability, and the realization of ultimate adult height [1]. Typically, the emergence of secondary sexual characteristics before the age of 8 in girls and before the age of 9 in boys is defined as precocious puberty, which can have serious implications for the physical and mental health of children [2]. Precocious puberty not only diminishes the final adult height [3], but also elevates the risk of developing cancer, metabolic issues, and infertility in adulthood [4–6]. Furthermore, it is linked with an increased occurrence of psychological and behavioral disturbances, including social anxiety [7], depression [8], substance abuse [9], eating disorders [10], and risky sexual behavior [11]. Therefore, as a prevalent endocrine disorder in pediatrics, precocious puberty has emerged as a public health issue, affecting children’s health, family dynamics and societal stability [12].

Over the past few decades, there has been a significant rise in the incidence of precocious puberty among children. This trend is often attributed to rapid socioeconomic development and substantial improvements in living conditions [13–19]. The notable increase has spurred numerous research investigating the prevalence and incidence of precocious puberty, especially in countries experiencing swift economic growth [20–23]. Estimates of the prevalence and incidence of precocious puberty vary widely worldwide, reflecting not only regional social and environmental differences but also variations in the measurement and reporting of the condition. The methods used to identify cases of precocious puberty differ significantly across studies. Some employ cross-sectional surveys in community or school settings, assessing secondary sexual characteristics via professional examination [21, 24, 25] or parental recall [26]. Others use diagnostic records or gonadotropin-releasing hormone agonist treatment data from national health insurance databases with diverse registration models [20, 22, 23]. This heterogeneity in epidemiological studies complicates our overall understanding of pubertal development [12]. Moreover, few studies have examined the prevalence or incidence of precocious puberty from a comprehensive global perspective or analyzed global incidence variation with different characteristics [12].

To address this gap, we conducted a systematic review and meta-analysis to estimate the global prevalence and incidence of precocious puberty among children. Given the increasing recognition of precocious puberty as a growing public health concern with potential long-term physical, psychological, and social implications, our study aimed to provide a comprehensive overview of its global epidemiological profile. By synthesizing available evidence, this work not only enhances the overall understanding of precocious puberty but also offers a critical reference for cross-regional comparisons, clinical management, and preventive strategies, thereby supporting future research and public health interventions.

Methods

Our study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline [27], and the systematic review protocol was registered in PROSPERO (registration number CRD42024508384) on February 1st, 2024.

Inclusion and exclusion criteria

We included studies if they met the following criteria: (1) Observational studies. (2) Participants were from general population, defined as apparently healthy children from schools, communities, or national demographic censuses. (3) The prevalence or incidence of precocious puberty in children was clearly reported. In our review, we used the current uniform standard to define precocious puberty. For girls, precocious puberty is defined as reaching Tanner stage II or higher in breast development or pubic hair development before the age of 8. For boys, it is defined as having a testicular volume greater than 4 ml or showing pubic hair development before the age of 9 [2]. (4) Pubertal assessments were performed by professional pediatricians using the Tanner staging method [28, 29], rather than relying on self-reported outcomes, to avoid misclassification and recall bias. (5) The sample size was greater than 100 to reduce the risk of low accuracy in estimating prevalence [30]. (6) Articles were published in English.

The exclusion criteria were applied to studies that met any of the following conditions: (1) Conference abstracts, letters, comments, duplicate publications, and unpublished studies. (2) Studies that only involved special groups, such as hospitalized patients or children in extremely unique growth environments that might affect growth and development (e.g., adopted children, immigrants, and abused children).

Search strategy and study selection

We searched the relevant literature through PubMed, Embase, and Web of Science databases from their inception to February 3rd, 2024. Search terms were designed by combining Medical Subject Headings words and keywords to identify the epidemiological studies related to precocious puberty. Search terns included: (“precocious puberty” OR “early puberty” OR “early maturation” OR “premature puberty”) AND (epidemiology OR incidence OR prevalence OR “cross sectional study” OR “cohort study” OR “longitudinal study”). We also performed a manual search by screening the reference lists of included studies and relevant reviews. The full search strategies are present in Supplementary Table 1.

Two reviewers (XYZ and LPY) independently screened titles and abstracts of retrieved records and reviewed full-text of potentially eligible studies. Any conflicts were resolved by discussion with a third reviewer (YJX) to reach a consensus.

Data extraction

Two reviewers (XYZ and LPY) independently extracted data from the included studies using a designed form. The following information was extracted: (1) Basic study characteristics: title, first author, year of publication, and country; (2) Study design details: study type, survey year, research setting, diagnostic criteria for precocious puberty, and methods used to assess secondary sexual characteristics; (3) Participant characteristics: age, sex, body mass index (BMI), total population size, number of girls under the age of 8 and boys under the age of 9, and number of cases; (4) Prevalence of precocious puberty, including overall prevalence rate, and prevalence rates stratified by age group and BMI; and (5) Incidence of precocious puberty, including overall incidence rate, annual incidence rate, and incidence rate by age group. The prevalence or incidence estimates were extracted and classified by gender. Any controversial findings during the extraction process were discussed and resolved through consensus. In cases where agreement could not be reached, a third reviewer (YJX) was consulted to provide an independent judgment, ensuring the accuracy and reliability of the extracted data.

Risk of bias assessment

Two reviewers (XYZ and LPY) independently assessed risk of bias of included studies using the Agency for Healthcare Research and Quality (AHRQ) methodological checklist. This tool was specifically designed for evaluating cross-sectional studies [31]. An item would be scored as “1” if it was answered “YES”, and as “0” if answered “NO” or “NOT CLEAR”. Article with a score of 8 to 11 was rated as high quality, a score of 4 to 7 as moderate quality, and a score of 0 to 3 as low quality. The inter-rater reliability for the risk of bias assessment was evaluated using Cohen’s kappa (κ). A kappa value greater than 0.75 was considered to indicate substantial agreement. Any disagreements were reviewed by consulting a third reviewer (YJX).

Data synthesis and meta-analysis

We calculated the prevalence by using the number of cases of precocious puberty as the numerator and the total population of the corresponding age group as the denominator (details of the calculation seen in Supplementary Table 2). For the prevalence of precocious puberty obtained from cross-sectional surveys, we calculated the standard error and pooled prevalence estimates with 95% confidence interval (CI) separately for girls and boys. We used a random-effects inverse-variance model to pool the prevalence estimates, taking into account the heterogeneity of the estimates. χ² test was used to evaluate statistical heterogeneity of results among included studies and I² statistic was used to quantify the level of heterogeneity, with higher values indicating greater heterogeneity. We also conducted subgroup analyses to detect possible sources of heterogeneity based on socioeconomic-level characteristics (e.g., geographical region, national income level, and survey year) and individual-level characteristics (e.g., age and BMI). Geographical regions were classified according to the continents: Asia, Europe, North America, South America, Africa, and Oceania. National income levels were categorized into four groups based on World Bank criteria: low income, lower-middle income, upper-middle income, and high income. Survey years were grouped into three periods: before 2000, 2000–2010, and after 2010. Age groups were defined as 6–6.9 years, 7–7.9 years, and 8–8.9 years. With respect to BMI, participants were classified into a normal weight group and an overweight/obese group. The definitions of overweight and obesity were adopted from the criteria used in the original studies. In addition, to assess the stability and reliability of the pooled estimates, a sensitivity analysis was performed by sequentially excluding each study from the meta-analysis. The remaining studies were then reanalyzed to determine whether the omission of any single study significantly altered the overall effect size.

For the prevalence and incidence data obtained from various national health insurance databases, we presented the specific results in a description form rather than pooling the data, due to the small number of studies and the high heterogeneity among studies from different countries.

All statistical analyses were performed using Stata 14.0 MP software. A two-sided P value < 0.05 was considered statistically significant.

Results

Literature search and study selection

A total of 8737 potentially relevant records were initially retrieved. Among them, 2684 duplicates were excluded, 5883 publications were excluded by reviewing titles and abstracts for consistency with the inclusion and exclusion criteria, and 170 potential studies were eligible for full-text screening. We eventually included 27 articles. The PRISMA flowchart of the literature search and study selection process is shown in Fig. 1.

Fig. 1.

The flowchart of the literature search and study selection

Characteristics of included studies

Of the 27 included studies, 10 were from Asia [13, 20, 24, 25, 32–37], 10 from Europe [22, 23, 38–45], 5 from North America [21, 46–49], and 2 from South America [50, 51]. The most common countries of origin were China (n = 7), the United States (n = 4), and Italy (n = 4). All articles were published between 1991 and 2023, with the survey years of the reported studies ranging from 1987 to 2020. Eleven studies (40.74%) were conducted after the year 2010. Most of the studies from Asia and low- and middle-income countries were conducted after 2010, while most of the studies from Europe and the United States, as well as those from high-income countries, were conducted before 2010. We extracted prevalence estimates from 24 studies (18 studies based on cross-sectional surveys and 6 based on medical registration data) and extracted incidence estimates from 9 studies (all based on medical registration data).

Overall, ten studies were rated as high quality and 17 were rated as moderate quality. A kappa value of 0.84 was obtained, indicating almost perfect agreement between reviewers. All included studies defined the data source, listed inclusion and exclusion criteria for subjects, and included subjects consecutively. However, more than half of the studies did not report reasons for excluding any participant from analysis (n = 16, 59.26%), did not explain how missing data were handled (n = 16, 59.26%), and did not report subject response rates (n = 15, 55.56%). The characteristics and risk of bias assessment of the included studies are shown in Supplementary Tables 3 and 4.

Prevalence of precocious puberty

Among the 18 survey-based studies [21, 24, 25, 32, 34–37, 40, 42–48, 50, 51], pubertal assessments were conducted by trained pediatricians using the Tanner staging method. For girls, the pooled prevalence of precocious puberty was estimated at 7.87% (95% CI: 5.90%−9.84%) (Fig. 2, Supplementary Fig. 1). The highest pooled prevalence was observed in South America (21.47%; 95% CI: 17.88%−25.06%), while the lowest was reported in Europe (3.23%; 95% CI: 1.08%−5.37%). Girls from upper-middle-income countries (9.74%; 95% CI: 5.34%−14.13%) and those surveyed between 2000 and 2010 (11.65%; 95% CI: 3.35%−19.96%) showed the highest prevalence compared to other subgroups. For boys, the pooled prevalence of precocious puberty was estimated at 3.98% (95% CI: 2.70%−5.25%) (Fig. 3, Supplementary Fig. 2). North America had the highest pooled prevalence among boys (13.02%; 95% CI: 10.92%−15.11%), whereas Europe reported the lowest (1.87%; 95% CI: 0.86%−2.87%). Boys from low-income countries (10.93%; 95% CI: 7.41%−14.45%) and those surveyed between 2000 and 2010 (10.44%; 95% CI: 5.32%−15.55%) also showed the highest prevalence across subgroups. It is important to note that data availability varied across regions and income levels. Specifically, only one study was available for girls from South America (n = 1), and no studies were reported from low-income countries (n = 0). For boys, studies from South America (n = 2), North America (n = 1), Europe (n = 1), low-income countries (n = 1), and surveys conducted before 2000 (n = 1) were limited. At the individual level, the prevalence of precocious puberty varied significantly by age group and BMI. Older children, specifically girls aged 7 to 7.9 years and boys aged 8 to 8.9 years, as well as overweight and obese children, showed a significantly higher prevalence compared to their counterparts. Detailed prevalence estimates across all subgroups are summarized in Table 1. The results of sensitivity analysis indicated that no individual study had a substantial impact on the pooled prevalence estimate, suggesting that the findings are stable and not overly dependent on any one study (Supplementary Figs. 3 and 4).

Fig. 2.

The forest plot of pooled prevalence of precocious puberty in girls (n = 15)

Fig. 3.

The forest plot of pooled prevalence of precocious puberty in boys (n = 10)

Table 1.

The prevalence of precocious puberty from studies based on cross-sectional surveys (n = 18)

	Girls		Boys
	No. of studies	Pooled prevalence, % (95% confidence interval)	No. of studies	Pooled prevalence, % (95% confidence interval)
Total	15	7.87 (5.90–9.84)	10	3.98 (2.70–5.25)
Study characteristics
Country
China	6	9.88 (5.00–14.76)	5	1.56 (0.39–2.73)
United States	3	7.76 (0.86–14.66)	1	13.02
Italy	3	1.81 (1.41–2.20)	1	1.87
Chile	1	21.47	2	10.62 (1.37–19.87)
Turkey	1	8.90	-	-
Lithuania	1	1.18	-	-
India	-	-	1	10.93
Continent
Asia	6	9.88 (5.00–14.76)	6	2.25 (1.04–3.46)
Europe	5	3.23 (1.08–5.37)	1	1.87
North America	3	7.76 (0.86–14.66)	1	13.02
South America	1	21.47	2	10.62 (1.37–19.87)
Income level
Low	-	-	1	10.93
Upper-middle	7	9.74 (5.34–14.13)	5	1.56 (0.39–2.73)
High	8	5.98 (4.04–7.91)	4	8.88 (2.14–15.62)
Survey year
After 2010	6	9.88 (5.00–14.76)	7	2.37 (1.15–3.59)
2000–2010	4	11.65 (3.35–19.96)	2	10.44 (5.32–15.55)
Before 2000	5	2.72 (1.56–3.87)	1	1.87
Age group
6-6.9y	6	3.85 (2.18–5.51)	3	5.77 (−2.29-13.83)
7-7.9y	7	7.04 (4.55–9.52)	4	2.86 (0.76–4.97)
8-8.9y	-	-	4	11.10 (3.82–18.38)
Body mass index
Normal	3	8.28 (1.31–15.25)	3	1.12 (0.06–2.17)
Overweight/obesity	3	33.15 (8.16–58.14)	3	2.98 (1.05–4.90)

Six registry-based studies extracted diagnostic data on precocious puberty from three national (South Korea [13, 20], Denmark [22], and Spain [23]) and two regional (Taiwan, China [33] and Tuscany, Italy [41]) health insurance databases. Four of these studies [20, 23, 33, 41] included girls younger than 8 years and boys younger than 9 years. The remaining two studies [13, 22] included girls younger than 9 years and boys younger than 10 years, taking into account the potential lag between the initial signs of puberty and the clinical diagnosis of precocious puberty. The overall prevalence of central precocious puberty varied widely across populations, ranging from 37 to 935.1 per 100,000 girls and from 0.46 to 37.4 per 100,000 boys. Given the substantial heterogeneity across studies, including variations in national versus regional health insurance databases, differences in diagnostic age thresholds, and limited numbers of available studies, we present the detailed findings in Table 2 rather than pooling the estimates.

Table 2.

The prevalence of precocious puberty from studies based on medical registration data (n = 6)

Author, year, Country	Data source	Cutoff age	Identification	Survey year	Girls	Boys
Kang, 2023, South Korea[13]	Korean Health Insurance Review Agency	girls <9y boys <10y	diagnosed with CPP and treated with GnRHa	2008–2020	overall prevalence: 935.1 per 100,000 girls annual prevalence: 98.8 (in 2008) to 2468.8 (in 2020) per 100,000 girls	overall prevalence: 37.4 per 100,000 boys annualprevalence: 1.9 (in 2008) to 1533 (in 2020) per 100,000 boys
Su, 2020, China[33]	Taiwan Health Insurance Research Dataset	girls <8y boys <9y	diagnosed with PP	2000–2013	overall prevalence: 222.6 per 100,000 girls annual prevalence: 100.5 (in 2000) to 447.9 (in 2013) per 100,000 girls	overall prevalence: 8.0 per 100,000 boys annual prevalence: 6.3 (in 2000) to 14.7 (in 2013) per 100,000 boys
Kim, 2015, South Korea[20]	Korean Health Insurance Review Agency	girls <8y boys <9y	diagnosed with CPP and treated with GnRHa	2004–2010	annual prevalence: 55.9 per 100,000 girls in 2010	annual prevalence: 1.7 per 100,000 boys in 2010
Soriano-Guillén, 2010, Spain[23]	Spanish National Institute of Statistics	girls <8y boys <9y	diagnosed with CPP and treated with GnRHa	1997–2009	annual prevalence: 37 per 100,000 girls in 2009	annual prevalence: 0.46 per 100,000 boys in 2009
Massart, 2005, Italy[41]	Northwest Tuscany Health Services	girls <8y boys <9y	diagnosed with CPP and treated with GnRHa	1998–2002	mean overall prevalence: 30.4 per 100,000 children, ranging from 18.7 (in Livorno) to 58.1 (in Massa) per 100,000 children
Teilmann, 2005, Denmark[22]	Danish National Patient Registry	girls <9y boys <10y	diagnosed with CPP	1993–2001	overall prevalence: 240.4 per 100,000 girls	overall prevalence: 30.1 per 100,000 boys

CPP central precocious puberty, GnRHa gonadotropin-releasing hormone agonist, PP precocious puberty

Incidence of precocious puberty

Of the 27 included studies, nine reported the incidence estimates of precocious puberty based on the registry data from five national (South Korea [13, 20], Denmark [22, 38], France [39], Spain [23], and Puerto Rico [49]) and two regional (Taiwan, China [33] and Tuscany, Italy [41]) health insurance databases (Table 3). Five studies [20, 23, 33, 41, 49] included girls younger than 8 years and boys younger than 9 years, while the remaining four studies [13, 22, 38, 39] included girls younger than 9 years and boys younger than 10 years. The overall incidence of central precocious puberty ranged from 1.123 to 489.3 per 100,000 girls and from 0.096 to 22.4 per 100,000 boys.

Table 3.

The incidence of precocious puberty from studies based on medical registration data (n = 9)

Author, year, Country	Data source	Cutoff age	Identification	Survey year	Girls	Boys
Kang, 2023, South Korea[13]	Korean Health Insurance Review Agency	girls <9y boys <10y	diagnosed with CPP and treated with GnRHa	2008–2020	overall incidence: 489.3 per 100,000 girls annual incidence: 88.9 (in 2008) to 1414.7 (in 2020) per 100,000 girls	overall incidence: 22.4 per 100,000 boys annual incidence: 1.2 (in 2008) to 100.0 (in 2020) per 100,000 boys
Bräuner, 2020, Denmark[38]	Danish National Patient Registry	girls <9y boys <10y	diagnosed with CPP	1998–2017	overall incidence: 92 per 100,000 girls annual incidence: 26 (in 1998) to 146 (in 2017) per 100,000 girls	overall incidence: 9 per 100,000 boys annual incidence: 1 (in 1998) to 21 (in 2017) per 100,000 boys
Su, 2020, China[33]	Taiwan Health Insurance Research Dataset	girls <8y boys <9y	diagnosed with PP	2002–2013	overall incidence: 201.8 per 100,000 person-year annual incidence: 99.5 (in 2002) to 357.7 per 100,000 (in 2013) person-year	overall incidence: 7.4 per 100,000 person-year annual incidence: 3.4 (in 2002) to 12.6 (in 2013) per 100,000 person-year
Le Moal, 2018, France[39]	French National Health Insurance Information System	girls <9y boys <10y	diagnosed with ICPP and treated with GnRHa	2011–2013	overall incidence: 26.8 per 100,000 girls	overall incidence: 2.4 per 100,000 boys
Kim, 2015, South Korea[20]	Korean Health Insurance Review Agency	girls <8y boys <9y	diagnosed with CPP and treated with GnRHa	2004–2010	overall incidence: 15.3 per 100,000 girls annual incidence: 3.3 (in 2004) to 50.4 (in 2010) per 100,000 girls	overall incidence: 0.6 per 100,000 boys annual incidence: 0.3 (in 2004) to 1.2 (in 2010) per 100,000 boys
Soriano-Guillén, 2010, Spain[23]	Spanish National Institute of Statistics	girls <8y boys <9y	diagnosed with CPP and treated with GnRHa	1997–2009	overall incidence: 1.123 per 100,000 girls annual incidence: 0.13 (in 1997) to 2.17 (in 2006) per 100,000 girls	overall incidence: 0.096 per 100,000 boys annual incidence: 0 (in 1998) to 0.23 (in 2009) per 100,000 boys
Massart, 2005, Italy[41]	Northwest Tuscany Health Services	girls <8y boys <9y	diagnosed with CPP and treated with GnRHa	2000–2003	overall incidence: 7.2 per 100,000 children ranging from 3.3 to 10.7 per 100,000 children
Teilmann, 2005, Denmark[22]	Danish National Patient Registry	girls <9y boys <10y	diagnosed with CPP	1993–2001	overall incidence: 30 per 100,000 girls	overall incidence: 4 per 100,000 boys
Larriuz-Serrano, 2001, Puerto Rico[49]	Puerto Rico Health Department	girls 2-8y	diagnosed with premature thelarche	1990–1995	overall incidence: 162 per 100,000 girls	-

CPP central precocious puberty, GnRHa gonadotropin-releasing hormone agonist, ICPP idiopathic central precocious puberty, PP precocious puberty

Discussion

This systematic review included 27 original studies and provided a comprehensive summary of the global prevalence and incidence of precocious puberty. We also conducted subgroup analyses to examine the association between prevalence and various socioeconomic and individual characteristics.

Precocious puberty has become a prevalent pediatric endocrine disorder in recent decades [2]. According to the initial definition established by Marshall and Tanner in the 1960s, the normal age range for the onset of puberty is when 95% of children show the first signs of puberty (i.e., 8–13 years in girls and 9–14 years in boys) [28, 29]. Under normal circumstances, about 2.5% of children start puberty early and 2.5% start puberty delayed [12, 14, 18]. In our review, the pooled prevalence estimates of precocious puberty were 7.87% for girls and 3.98% for boys, representing a significant increase compared to the historical norms. This finding indicated a clear trend toward earlier pubertal timing, which was consistent with current research. The age at thelarche has been reported to decrease by approximately 10 months from 1977 to 2013 [52], and the age at menarche has decreased by 2.5 to 4 months over the past 25 years [53, 54]. Similarly, there has been a reduction of 3 months in the age at pubertal onset in boys over the recent 15-year period [55]. The decline in pubertal onset is primarily linked to external environmental changes, including advancements in healthcare, improved fetal nutrition and childhood diets, and enhanced sanitation since the mid-20th century [18]. Additionally, modern lifestyles, such as increased sedentary behavior, excessive use of electronic devices, and exposure to endocrine-disrupting chemicals, may influence reproductive system maturation [15, 16]. Consequently, the earlier onset of puberty can be partly viewed as a byproduct of rapid industrial societal development.

However, evidence supporting earlier pubertal onset has incited debates among pediatric endocrinologists about the cutoff age for precocious puberty [2, 14–16]. The Lawson Wilkins Pediatric Endocrine Society recommended redefining the age limit to seven years for white girls and six years for African-American girls [56]. The 2022 Chinese expert consensus on the diagnosis and treatment of central precocious puberty modified the cutoff age to 7.5 years for girls [57]. On the other hand, there is notable opposition. Increased childhood obesity rates may contribute to earlier puberty in girls [15]. In the absence of red flags, some cases of precocious puberty may simply reflect normal development variation [17]. This has led to ongoing debates about whether early pubertal signs truly represent pathological development or simply reflect a shift in the normal distribution of pubertal timing. At present, the available evidence has been not yet robust enough to warrant conclusive recommendations for revising the diagnostic criteria of precocious puberty. Consequently, both medical practitioners and policymakers continue to adopt a cautious stance toward potential changes. Recent guidelines from Italy [16], South Korea [58], Russia [59], and Mexico [60] still use the original diagnostic criteria, as do all the studies included in our review. Setting a higher diagnostic cutoff age may lead to overdiagnosis by classifying early but physiologically normal pubertal development as precocious puberty. This could result in unnecessary medical evaluations and interventions. Conversely, lowering the threshold too far may miss children who exhibit clinically relevant pubertal changes and require timely management, potentially leading to underdiagnosis. Therefore, any adjustment to the age cutoff for diagnosing precocious puberty should be supported by extensive, multicenter, population-based studies. Any change of six months, one year, or two years should also consider regional differences in pubertal development patterns.

Pubertal timing in boys has historically received less attention compared to girls, with no debate about the age limit for precocious puberty in boys [18]. Traditional perspectives suggest that precocious puberty occurs far more frequently in girls than in boys, with female-to-male ratios ranging from 15:1 to 20:1 [14, 16]. However, our pooled data revealed a more moderate sex disparity, with prevalence estimates of 7.87% for girls and 3.98% for boys. Historical data indicated no significant trend towards earlier puberty onset in boys from the 1960 s to the 1990 s [61]. Until recent 15 to 20 years, some studies have reported a slight trend towards earlier puberty in boys, with a 3-month decline between 1991 and 2008, coinciding with increased luteinizing hormone levels [55]. Improvements in nutrition and overall health have contributed to this early onset, although the shift was smaller than that observed in girls. In our review, studies from Chile [51], the United States [46], and India [37] reported precocious puberty prevalence in boys exceeding 10%. These higher estimates may be influence by smaller sample sizes (less than 1000 participants) and variability in the methods used to assess pubertal characteristics. In contrast, other studies reported much lower prevalence estimates, highlighting the need for more robust, population-based data to better characterize the true burden of precocious puberty in boys.Therefore, more data are needed to achieve a comprehensive understanding of the true prevalence of precocious puberty in boys. Importantly, up to 50%−70% of boys diagnosed with central precocious puberty have identifiable hypothalamic-pituitary organic lesions, often linked to genetic mutations [16, 19, 62]. Thus, precocious puberty in boys warrants attention, and specialist evaluation is advisable even if the condition appears benign [17]. Identifying underlying pathological causes requires a comprehensive assessment of pubertal progression, skeletal maturation, and growth tempo [18].

Subgroup analyses demonstrated that social and economic factors significantly influenced the variation in the prevalence of precocious puberty. Surveys from various regions showed a distinct chronological pattern, with studies in Europe and the United States typically predating those in Asia. This pattern implies that the timing of the emergence of and concern about precocious puberty correlates with the sequence of global socioeconomic development [18]. In high-income countries, well-off conditions can accelerate pubertal development, while this phenomenon is delayed in low- and middle-income countries, depending on the rate of improvements in living conditions [63]. Therefore, socioeconomic and nutritional disparities may account for significant variations in the prevalence of precocious puberty [15, 18, 63]. We observed that most recent studies on precocious puberty over the past five years have been conducted in China, indicating that this condition has become a growing public health issue in the country. This finding highlights the need for enhancing awareness, early detection, and clinical management of precocious puberty in developing countries experiencing rapid socioeconomic transitions, such as China. Furthermore, coordinated efforts are needed to address potential dietary and environmental influences on child development, to safeguard the physical and psychological well-being of children and adolescents.

Additionally, BMI is significantly associated with the heterogeneity in the prevalence of precocious puberty. Subgroup analyses showed that the prevalence of precocious puberty in overweight and obese girls was four times higher than in normal-weight girls, with a smaller gap observed in boys. As common pediatric conditions, precocious puberty and obesity share some common causes (e.g., adequate nutrition and lack of physical activity) and similar consequences (e.g., psychological disorders and metabolic abnormalities) [64]. These two conditions in girls have also been reported to be independent risk factors for each other [65]. This may be due to excessive sex steroids from precocious puberty leading to obesity [66], or obesity-related leptin initiating precocious puberty [36]. Although few studies have explored the potential pathological mechanisms linking precocious puberty and obesity [64], a strong positive relationship is well-documented [67–69]. Thus, addressing obesity-related factors could mitigate the trend towards earlier puberty development.

Strengths and limitations

To our knowledge, this is the first systematic review to report the global prevalence and incidence of precocious puberty among children. Our findings could provide a reference for the debate on the definition of precocious puberty and offer new insights for the formulation of guidance on pubertal development in different countries. Considering the heterogeneity, we presented the outcomes separately based on the different case identification methods for precocious puberty. Prevalence estimates obtained from cross-sectional surveys and national health databases varied widely, with the former generally being much higher. One possible explanation is that some children diagnosed with precocious puberty in cross-sectional surveys may have non-progressive or slowly progressive forms of the condition, which often do not require medical intervention. In contrast, cases identified through national health databases are more likely to represent clinically significant and rapidly progressive forms that necessitate hormonal therapy. Another contributing factor is the typical lag period. It often lasts one year or more between the onset of precocious puberty signs, parents noticing the symptoms, clinic visits, diagnosis, and the need for hormone therapy [22, 23]. Furthermore, there is a significant possibility that cases of precocious puberty may be missed at each stage [13]. Therefore, our findings suggest that each method for assessing the prevalence of precocious puberty has its advantages and disadvantages. This highlights the importance of carefully considering the case-ascertainment methods when comparing and interpreting prevalence estimates across studies.

Our study has several limitations. First, although the definition of precocious puberty proposed by Marshall and Tanner in the 1960s is somewhat controversial, we still used this definition in the inclusion and exclusion criteria. This is because there is no other widely accepted standard, and this definition remains commonly used in current epidemiological studies. Second, we did not distinguish between subtypes of precocious puberty, such as central and peripheral, or idiopathic and pathological, primarily due to the limited information provided by the included studies. If subgroup analyses had included comparisons of these subtypes, they would have provided more detailed insights into the developmental status and offered greater guidance in understanding precocious puberty. Third, the studies we included exhibited significant heterogeneity and were also limited in number. Due to the variations in national or regional registration models, we were unable to provide a pooled incidence of precocious puberty. Additionally, to minimize potential biases in estimating the prevalence of precocious puberty and in analyzing research trends resulting from uneven publication distributions across languages, we included only articles published in English and did not search our local databases. Nevertheless, we acknowledge that this approach may not fully eliminate language-related biases among studies. For instance, our included studies lacked research from Africa and Oceania.

Conclusions

This systematic review and meta-analysis provided the first comprehensive overview of the global prevalence and incidence of precocious puberty in children. Based on survey data, the pooled prevalence was estimated at 7.87% for girls and 3.98% for boys, whereas registry-based studies showed considerable variation in incidence rates. These differences in prevalence were associated with socioeconomic factors and individual characteristics, highlighting the need for increased attention to children in rapidly developing countries and those with obesity.

For healthcare providers and policymakers, there is a pressing need to enhance public awareness, promote early detection, and implement integrated management strategies for precocious puberty, while also addressing the impact of nutritional and environmental factors on children’s development. However, significant heterogeneity was observed across the included studies. To gain a more accurate and comprehensive understanding of the global burden of precocious puberty, further large-scale, population-based studies are essential. Such research will help refine our knowledge and inform more effective public health strategies.

Authors’ contributions

XYZ, YJX, and LPY conceptualized and designed the study, screened the studies, extracted all data, conducted the meta-analysis, and drafted the initial manuscript. XYW and JYX completed bias assessment and revised the manuscript. GC and FW settled controversial findings and critically revised the manuscript. All authors read and approved the final manuscript.

Funding

This study was supported by National Natural Science Foundation of China (Grant number: 82304135). The funder had no role in the design and conduct of the study.

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.