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Birth weight, early childhood weight status influence age at menarche
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A lower birth weight, greater BMI and weight gain in infancy and early childhood are independently associated with earlier age at menarche, according to a meta-analysis.
“The secular trend toward earlier menarche, and whether it is reason for concern, is the subject of scientific controversy,” Filippa Juul, a PhD student at the College of Global Public Health at New York University, and colleagues wrote. “While the decline in menarcheal age is likely associated with improved living conditions, better nutrition, health and advancement in medicine, it is hypothesized that exposures to excess adiposity in childhood, physical inactivity, environmental endocrine disrupting chemicals (EDCs) and unhealthy diets may be contributing factors.”
Juul and colleagues analyzed data from 17 interventional or observational studies assessing age at menarche or the risk for early menarche and the influence of birth weight (n = 3), infancy/childhood weight status or gain (n = 4) or both (n = 10).
Researchers observed an association between birth weight and age at menarche in 10 of 13 longitudinal studies assessing the relationship, with several studies noting a linear trend toward earlier menarche with lower birth weight across birth weight categories. In nine studies assessing early-life weight gain and age at menarche, including exposure at multiple age intervals, researchers found that age at menarche was associated with weight or BMI gain over time for at least one of the investigated time periods. Additionally, greater weight gain between 0 and 24 months — measured as change in BMI ranks, BMI z score, weight standard deviation score or weight z score — was associated with increased risk for early age at menarche in four studies.
In a U.S. study of 338 girls, researchers observed that each BMI increment from age 36 months until first grade (mean age, 7 years) was associated with a 75% increased risk for attaining menarche by sixth grade (mean age, 12 years; OR = 1.75; 95% CI, 1.06-2.91). In seven studies evaluating the association between early life weight status and age at menarche, researchers observed a positive association for at least one assessed time point in six studies.
The researchers noted that findings regarding the influence of different levels of birth weight on age at menarche were inconsistent — and in one case contradictory — and attributed the divergent results to studies using different analytical approaches and birth weight measures, such as birth weight in grams, birth weight z score and expected birth weight ratio, complicating comparability.
“Studies generally suggested that lower birth weight as well as higher body weight and weight gain in infancy and childhood may increase the risk of early menarche,” the researchers wrote. “Subsequently, prenatal life, infancy and childhood may represent opportunities to prevent early menarche. From a clinical standpoint, these findings highlight the importance of appropriate maternal and child health care to optimize health outcomes.” – by Regina Schaffer
Disclosures: The authors report no relevant financial disclosures.
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