Growth and maturation during adolescence has not been well described in rural African populations, although it may represent the missing link between high levels of preschool stunting and nearly 'normal' adult heights. In 1995 the homes of subjects aged 10.3-17.5 years, living in a rural area of Senegal, were visited, and all adolescents present, 1527 boys and 1126 girls, were included in the analysis. A number of girls were absent because they worked in the capital city Dakar. Resident girls (n = 705) had significantly higher means than boys for all anthropometric variables (weight, body mass index, arm circumference and muscle arm circumference, triceps and subscapular skinfolds), except for height and head circumference. Girls who had just returned from seasonal migration to Dakar (n = 415) were, on average, 2 kg heavier, but not taller, than resident girls (p < 0.0001). The girls fell off in height from 11 to 13 years compared to the NCHS reference and then 'caught up' until the age of 17, while boys fell off during the entire age span. Mean age at menarche was estimated at 16.1 years (95% fiducial CI: 15.8-16.4) from status quo data by probit analysis. No significant difference was found between residents and migrants. Postmenarcheal girls had better nutritional status than premenarcheal girls in terms of height, weight, body mass index, percentage body fat and arm muscle circumference (p < 0.0001). In conclusion, puberty, as assessed by age at menarche, is delayed by about 3 years in this population, probably due to malnutrition.

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).

These findings support the hypothesis that an agent present in well water plays an etiologic role in ALS. Further study of water use among individuals with ALS is warranted.

Aim:We previously reported that incidence rates for chronic lymphocytic leukemia (CLL) among US states are significantly correlated with levels of residential radon (RR). Because these correlations could be influenced by confounding and/or misclassification among large geographic units, we reinvestigated them using smaller geographic units that better reflect exposure and disease at the individual level.Methods:We examined the relationships between CLL and RR per county in 478 counties with publicly-available data.Results:After adjustment for ultraviolet radiation, a possible risk factor for CLL, county rates for CLL and RR were significantly correlated among males and females both together and separately (p < 0.0001).Conclusion:CLL is significantly associated with RR at the county level.

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