Date Published: April 24, 2007
Publisher: Public Library of Science
Author(s): Ken K Ong, Kate Northstone, Jonathan CK Wells, Carol Rubin, Andy R Ness, Jean Golding, David B Dunger, Andrew Prentice
Abstract: BackgroundEarly menarche tends to be preceded by rapid infancy weight gain and is associated with increased childhood and adult obesity risk. As age at menarche is a heritable trait, we hypothesised that age at menarche in the mother may in turn predict her children’s early growth and obesity risk.Methods and FindingsWe tested associations between mother’s age at menarche, mother’s adult body size and obesity risk, and her children’s growth and obesity risk in 6,009 children from the UK population-based Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort who had growth and fat mass at age 9 y measured by dual-energy X-ray absorptiometry. A subgroup of 914 children also had detailed infancy and childhood growth data. In the mothers, earlier menarche was associated with shorter adult height (by 0.64 cm/y), increased weight (0.92 kg/y), and body mass index (BMI, 0.51 kg/m2/y; all p < 0.001). In contrast, in her children, earlier mother's menarche predicted taller height at 9 y (by 0.41 cm/y) and greater weight (0.80 kg/y), BMI (0.29 kg/m2/y), and fat mass index (0.22 kg/m2/year; all p < 0.001). Children in the earliest mother's menarche quintile (≤11 y) were more obese than the oldest quintile (≥15 y) (OR, 2.15, 95% CI 1.46 to 3.17; p < 0.001, adjusted for mother's education and BMI). In the subgroup, children in the earliest quintile showed faster gains in weight (p < 0.001) and height (p < 0.001) only from birth to 2 y, but not from 2 to 9 y (p = 0.3–0.8).ConclusionsEarlier age at menarche may be a transgenerational marker of a faster growth tempo, characterised by rapid weight gain and growth, particularly during infancy, and leading to taller childhood stature, but likely earlier maturation and therefore shorter adult stature. This growth pattern confers increased childhood and adult obesity risks.
Partial Text: Rising rates of obesity in young children, even at preschool ages , indicate that future preventative strategies against childhood and subsequent adult obesity will require the identification of their very early predictive factors. In adults, early age at menarche is a strong risk factor for increased risk of obesity in women [2–4]. However, the causal direction and mechanism behind this association are debatable, as girls with earlier menarche are more likely to be overweight even before the onset of puberty [5,6]. The link between earlier menarche and adult obesity may simply be due to their common association with previous overweight. Rapid infancy weight gain may be the common aetiological factor, as this early growth pattern is predictive for both earlier menarche and increased obesity risk [7,8]. The 1946 British National Birth Cohort showed that women with earlier menarche had rapid growth during the first 2 y of life followed by average growth rates between ages 2 through 7 y . In contemporary birth cohort studies rapid infancy weight gain also predicts subsequent obesity risk in children and adults .
ALSPAC is a prospective study recruited from all pregnancies in three Bristol-based District Health Authorities with expected dates of delivery between April 1991 and December 1992, comprising 13,971 live births surviving to 1 y of age [13,14]. Birth weights were noted from hospital records and supine length was measured using a Harpenden neonatometer (Holtain Ltd, http://www.anthropometer.com) soon after birth (median 1 d, range 0–14 d) by the ALSPAC study team. Gestation was estimated using the date of last menstrual period and confirmed by antenatal ultrasound reports; in cases of discrepancy the data were reviewed by a single experienced clinician. Mother’s parity and smoking during pregnancy were recorded by a questionnaire completed during pregnancy. The mother’s highest educational achievement was recorded by questionnaire as an indicator of her socioeconomic status. Ethical approval was obtained from the ALSPAC and the local research ethics committees. Signed consent for anthropometry was obtained from a parent or guardian and verbal assent was obtained from the children.
In the mothers, early age at menarche was linearly associated with reduced adult height (by 0.64 cm/y; p < 0.001), but increased adult body weight (0.92 kg/y; p < 0.001) and BMI (0.51 kg/m2/y; p < 0.001; Table 1). Compared with the oldest menarche quintile (≥15 y old), those mothers in the earliest menarche quintile (≤11 y) had a 5-fold increased risk of obesity (OR 5.11, 95% CI 3.41–7.67; p < 0.001, adjusted for mother's age and education). Our data from a large, representative UK birth cohort show that earlier mother's age at menarche is a marker not only for her own obesity risk, but is also associated with faster weight gain and growth during infancy, and increased fat mass and obesity risk in her children. These findings suggest that the consistent association between rapid infancy weight gain and later obesity risk  has an inherited or transgenerational component. Source: http://doi.org/10.1371/journal.pmed.0040132