The purpose of this study was to review published studies on the variability of age at menarche and age at menopause throughout the world, and to identify the main causes for age variation in the timing of these events. We first present a summary table including mean (or median) values of the age at menarche in 67 countries, and of the age at menopause in 26 countries. General linear models showed that mean age at menarche was strongly linked to the mean female life expectancy, suggesting that one or several variables responsible for inequalities in longevity similarly influenced the onset of menarche. A closer examination of the data revealed that among several variables reflecting living conditions, the factors best explaining the variation in age at menarche were adult illiteracy rate and vegetable calorie consumption. Because adult illiteracy rate has some correlation with the age at which children are involved in physical activities that can be detrimental in terms of energy expenditure, our results suggest that age at menarche reflects more a trend in energy balance than merely nutritional status. In addition, we found the main determinant of age at menopause to be the mean fertility. This study thus suggests that, on a large scale, age at menarche is mainly determined by extrinsic factors such as living conditions, while age at menopause seems to be mainly influenced by intrinsic factors such as the reproductive history of individuals. Finally, these findings suggest that human patterns cannot be addressed solely by traditional, small-scale investigations on single populations. Rather, complementary research on a larger scale, such as this study, may be more appropriate in defining some interesting applications to the practical problems of human ecology.

Available data on the long-term consequences of preschool stunting are scarce and conflicting. The objective of this study was to assess the amount of catch-up growth from preschool stunting and the effect of migration (change in environment) during adolescence. A cohort study from preschool age (1-5 y) to adulthood (18-23 y) was conducted among 2874 subjects born in a rural area of Senegal. The subjects were divided into 3 groups of preschool stunting: none, mild, and marked, with height-for-age Z-scores of >-1, -2 to -1, and <-2, respectively. At follow-up, the history of migration was recalled. Mean height was 161.3 cm for girls and 174.0 cm for boys (>/=20 y). Stunted subjects remained smaller than the others: the age-adjusted height deficit between the 2 extreme categories was 6.6 and 9.0 cm in girls and boys, respectively. However, their height increment from early childhood to adulthood differed (69.3, 70.5, and 72.0 cm, P = 0.0001, and 78.9, 80.0, and 80.3 cm, P < 0.01, for nonstunted, mildly stunted, and markedly stunted girls and boys, respectively). The duration of labor migration to the city was associated with height increment in girls only in a nonlinear relation (adjusted means: 67.2, 69.3, 67.4, and 67.7 cm for 4 groups of increasing duration, P < 0.01). In conclusion, Senegalese children caught up in height prior to adulthood, with the adult means approximately 2 cm below the WHO/NCHS reference. However, this global catch up did not reduce height differences between formerly stunted and nonstunted children to any greater extent and it was not enhanced by labor migration.

Objective: To study the long-term impact of stunting during infancy on maturation, growth and fat distribution in adolescence. Design: A cohort of 406 Senegalese adolescent girls of rural origin underwent clinical and growth assessments every year from 1995 to 1999. Subjects: Mean coverage rate was 82% at each round. Adolescent girls were 11.4 AE 0.5 y of age in 1995 and 15.5 AE 0.5 y of age in 1999. Their growth status during infancy was known. About 20% of the girls had a height ± age (H ± age) below À2 Z-scores (chronic malnutrition or stunting) when they were 6 ± 18 months of age. As adolescents, the girls were divided into two groups on the basis of H ± age: those stunted and those non-stunted during infancy. Measurements: Sexual maturation was assessed by stage of breast development and menarche. Height, body mass, sitting height, bi-iliac and bi-acromial diameters, and six skinfolds were measured. Results: Differences in sexual maturation between previously stunted and non-stunted girls were not signi®cant. Girls stunted at infancy caught up in body weight and subcutaneous fat mass during puberty, but they did not catch up on stature, sitting height or skeletal breadths (bi-acromial and bi-iliac diameters) until the ®nal observation in 1999. Stunted girls did not have less subcutaneous fat (sum of six skinfolds) or a lower BMI. Regional variation in subcutaneous fat distribution (Z-score pro®le) indicated greater accretion at the biceps and subscapular sites in stunted compared to the non-stunted girls. Regional fat distribution was also assessed by principal component analysis (PCA) performed on the residuals of the six skinfolds measured during the ®nal round (1999). PCA identi®ed three components. Stunted and non-stunted girls were similar for the ®rst (trunk ± extremity contrast) and second (anterior ± posterior contrast) components. However, there was a difference for the third component: stunted girls tended to accumulate more subcutaneous fat on the upper part of the body (trunk or arms) than nonstunted girls. Conclusion: Stunted Senegalese girls have a potential for catching up in growth during puberty. The greater accumulation of subcutaneous fat on the upper body in stunted girls may be a consequence of complex hormonal adjustments at the onset of puberty. Sponsorship: Institut de Recherche pour le De Âveloppement (IRD anciennement ORSTOM) and the Nestle  Foundation.

Objective: To study the impact of preschool stunting on adolescent height and age at menarche in rural West Africa. Design: A longitudinal, population-based study. Setting: The Niakhar study area in Central Senegal. Subjects: 1650 children aged 12±17 y with known height-for-age at the age of 2±5 y. Main outcome measures: Adolescent height; mean age at menarche of girls estimated by the status quo method. Results: The subjects were divided into three groups of preschool height-for-age:`72, 72 to 71 and b 71 z-score of the NCHS reference. The mean height during adolescence differed signi®cantly according to preschool height-for-age for both boys and girls (P`0.001). Relative risk of adolescent stunting according to preschool stunting varied from 2.0 ± 4.0 depending on age and sex. Estimated mean age at menarche was 17.2 (95% ®ducial con®dence interval: 16.6 ±18.7), 16.5 (16.1±17.2) and 15.6 (15.2±16.0) y, respectively, for the three groups of preschool height-for-age (P`0.001). Mean increment from age 5 y to adolescence did not differ signi®cantly among the boys according to preschool stunting, but among the girls aged 16 ±17 y, the increment was higher for those who had been stunted during preschool life (P`0.01). Conclusion: Some evidence of catch-up growth between the ages of 5 and 17 y was found for stunted girls. The signi®cant delay in sexual maturation of the stunted girls suggests that stunted children of both sexes have a possibility of catch-up growth after the age of 17 y. Sponsorship: The preschool study was supported by the EEC (TSD-036).

Obesity is a worldwide public health problem impacting not only industrialized nations but also developing countries. The main objective of this paper was to analyze risk factors for overweight among Amerindian children and their mothers. Data were collected in 15 Amerindian riverside communities from the Beni River (Bolivia). The total sample was of 195 mothers and 452 children, 0–15 years of age. Information about family activity and dietary patterns was collected, and a clinical examination was performed. Stool samples were collected in children for parasitological screening. Anthropometric measurements, including weight, height, arm circumference, and four skinfolds, were taken. A bioelectrical impedance analysis was performed in mothers. In total, 12.2% (95% confidence interval (CI95%) 9.1–15.9%) of the children were considered overweight; less than 1% were overtly obese International Obesity Task Force (IOTF) criteria. Among their mothers, 35.3% (CI95%, 28.7–42.5%) were overweight (BMI (weight/height 2) >25 kg/m2), and 5% (CI95%, 2.5–5.1%) were obese (BMI >30 kg/m2). BMI was moderately related to anthropometric indices of body composition in children, but was highly correlated with fatness in mothers. The risk of overweight was not associated with environmental factors in children. In mothers, there was a significant relationship between BMI, health status, and dietary diversity score. There was a moderate association in boys between fatness and the BMI of their mothers (R2 = 0.12, P < 0.001), but not in girls. These findings suggest a trend toward accumulation of fat related to possible changes at the economic and agricultural levels, even in remote rural areas. Am. J. Hum. Biol. 19:61–73, 2007. © 2006 Wiley‐Liss, Inc.