Table 1.

Summary of included studies

Authors	Year	Country	Study Design	Primary Outcome	Sex	Sample Size (n)	Age (y)	Data Collection
Lian et al21	2019	China	Cross‐sectional	Puberty starts earlier in Chinese Han girls with obesity compared with Chinese Han girls with normal weight.	Girls	2996	9‐19	2012 and 2013
Biro et al12	2018	USA	Longitudinal	Body mass index had a greater effect on age at menarche than did race and ethnicity.	Girls	946	6‐16	2004‐2014
Lazzeri et al20	2018	Italy	Cross‐sectional	Overweight during childhood shows a relation with the early onset of puberty in girls.	Girls	6535	11	2009/2010
					Girls	4259	15	2013/2014
Li et al23	2018	China	Longitudinal	For both, boys and girls, a higher BMI (ie, overweight and obese) is associated with earlier onset of puberty	Boys	695	5.8‐12.2	2014‐2017
					Girls	542
Deng et al22	2017	China	Cross‐sectional	Increased BMI is associated with early timing spermarche and menarche.	Boys	1278258	9‐15	2005‐2012
					Girls
Flom et al15	2017	USA	Prospective birth cohort	Overweight/obese status at the age of 7 ye was associated with increased risk of early menarche	Girls	788	From birth to menarche occurred	Pregnancies 1959‐1966
He et al24	2017	China	Cross‐sectional	Onset of puberty is not related to obesity in boys.	Boys	782	7‐17
Holmgren et al17	2017	Sweden	Longitudinal	Higher BMI during childhood is associated with early puberty.	Boys	972		2008 and
					Girls	929		2009
Kelly et al19	2017	UK	Longitudinal prospective cohort	Higher BMI in girls is associated with the onset of menstruation at an earlier age.	Girls	5839	11	2000‐2002
Barcellos Gemelli et al25	2016	Brazil	Cross‐sectional	Excess weight is associated with early age of menarche.	Girls	727	10‐18	2014
Glass et al16	2016	USA	Longitudinal	In girls, but not in boys, greater adiposity is associated with the earlier onset of puberty.	Boys	123	11‐17	2003‐2009
					Girls	135
Lee et al26	2016	USA	Cross‐sectional	Boys with overweight enter puberty earlier compared with boys with normal weight or obesity, while puberty starts later in boys with obesity compared with boys with normal weight and overweight.	Boys	3872	6‐16	2005‐2010
Cabrera et al27	2014	USA	Cross‐sectional	Thelarche occurred earlier than recently reported, while age of menarche remained unchanged.	Girls	610	3‐17.9	2007
Leonibus et al14	2013	Italy	Longitudinal	Obesity during childhood is related to the earlier onset of puberty.	Boys	71		2005‐2012
					Girls	84
Currie et al13	2012	Europe, USA, Canada	Cross‐sectional	Overweight/obesity during childhood predicts the early onset of puberty in girls.	Girls	20410	11, 13, 15	2005‐2006
Herman‐Giddens et al28	2012	USA	Cross‐sectional	Observed mean ages of beginning genital and pubic hair growth and early testicular volumes were earlier than in past studies, depending on the characteristic and race/ethnicity.	Boys	4131	6‐16	2005‐2010
Sorensen et al29	2010	Denmark	Cross‐sectional/longitudinal	Puberty onset at earlier ages was associated with an increased BMI in boys.	Boys	1528	5.8‐19.9	1991‐1993/2006‐2008
Aksglaede et al30	2009	Denmark	Longitudinal	The higher BMI in boys and girls at 7 y of age, the earlier they enter puberty.	Boys	21 612		1930‐1969
					Girls	135 223
Juul et al31	2007	Denmark	Retrospective cohort	Higher BMI is associated with early voice break.	Boys	463	11‐15	1990‐1999
Ribeiro et al32	2006	Portugal	Cross‐sectional	Early sexual maturation in boys and girls is associated with overweight.	Boys	382	10‐15
					Girls	437
Kaplowitz et al18	2001	USA	Cross‐sectional	The early onset of puberty in Caucasian girls is likely related to an increased BMI.	Girls	10 750	5‐12	1992‐1993

Abbreviation: BMI, body mass index.