Journal of Obesity

Research Article

Mendelian Randomisation Study of Childhood BMI and Early Menarche

Longitudinal studies reporting the association between childhood BMI and subsequent age at menarche.


Reference (country)	Number of participants	Mean age at BMI assessment	Mean age at followup	Findings

Ong et al. 2009 (UK) [33]	1,781	9 mo 19 mo	13 y	Mean ± SE BMI by age at menarche
					<12 y	12-13 y	>13 y	value for trend
				(i) 9 mo	17.5 ± 0.1	17. 3 ± 0.1	17.3 ± 0.1	.007
				(ii) 19 mo	16.9 ± 0.1	16.7 ± 0.1	16.7 ± 0.1	.09

Buyken et al. 2009 (Germany) [34]	87	7.7 y (Interquartile range 6.5–8.8)	13 y	Age at menarche (mean, 95% CI) by BMI z-score 1 year before height “take-off”
				(i) Lowest BMI quartile		12.9 y	(12.4–13.4)	value for trend
				(ii) Quartiles 2 and 3		11.7 y	(11.4–12.1)	.03
				(iii) Highest BMI quartile		12.4 y	(11.9–12.8)

Lee et al. 2007 (USA) [36]	354	3.0 y 4.5 y 6-7 y	12 y	Odds ratio (95% CI) for early menarche (by age 12 y) per +1 BMI z-score
				(i) 3.0 y	OR = 1.45	(1.10–1.93)
				(ii) 4.5 y	OR = 1.50	(1.14–1.97)
				(iii) 6-7 y	OR = 1.85	(1.38–2.47)

Must et al. 2005 (USA) [35]	307	12.0 y (SD 1.2)	15 y	Age at menarche showed an inverse trend with premenarche BMI Correlation coefficient = −0.10; .

Freedman et al. 2003 (USA) [31]	771 Whites 408 Blacks	8.7 y (SD 2) whites 8.9 y (SD 2) blacks	17 y	Odds ratio (95% CI) for early menarche (<12 y) per +1 BMI z-score
				White girls	OR = 2.0	(1.6–2.5)
				Black girls	OR = 2.1	(1.5–3.0)