Expected gain in body mass and onset of the menarche

Role of lifetime body mass index in the association between age at puberty and adult lipids: findings from men and women in a British birth cohort

Purpose

Why early puberty is associated with worse cardiovascular outcomes is unknown. The relationship between puberty and lipids is unclear. Our aim was to assess whether age at puberty was associated with triglyceride and total low-density lipoprotein and high-density lipoprotein cholesterol at age 53 years.

Methods

Participants in a national birth cohort were examined at 15 years, when pubertal stage for boys was assessed and age at menarche reported by the girls' mothers. At 53 years, 3035 were interviewed in their homes by research nurses, where blood was taken.

Results

There was a significant inverse relationship in women but not men between age at puberty (in years) and triglycerides (regression coefficient −0.2.9, 95% confidence interval −5.5, to −0.04, p = .02), age at puberty, and age at puberty and adult body mass index (BMI; p < .001). Relationships between puberty and lipids were completely explained by BMI or waist circumference at 53 years.

Conclusions

In both sexes earlier maturation was associated with greater BMI and waist circumference in later life, which resulted in greater triglycerides and cholesterol in women. We suggest that intervention after puberty to help avoid obesity in early maturing women may improve their later cardiovascular health.

Effect of sub-elite competitive running on bone density, body composition and sexual maturity of adolescent females

The attainment of optimal peak bone mass during adolescence is important in the primary prevention of osteoporosis. Exercise may contribute to skeletal development and bone density during growth, although competitive exercise is suggested to have an adverse effect. This study assesses the effect of moderate exercise on the bone density of adolescent females. Additionally, other factors which significantly influence attainment of peak bone mass were identified. This was a cross-sectional study of 42 adolescent females, classified as runners (n=15) or non-runners (n=27). Nutrient intake, energy expenditure, menstrual history and pubertal stage were recorded. Bone age, skinfold thickness, body composition and bone mineral density (BMD) of total body, lumbar spine and proximal femur were measured. Statistical analyses used Student's t-test, Pearson correlation and multiple regression analyses. Runners had lower fat mass and higher lean mass, with a trend to higher BMD in all sites measured. There were no significant differences in menstrual cycle regularity, age at menarche or number who had attained menarche. Pubic hair development was similar in both groups. Breast development was delayed in runners, although this may have been a function of lower fat mass in this group. When subjects were categorized according to menarchal status, postmenarchal girls were significantly taller and heavier, with higher fat mass and significantly higher total body and lumbar spine BMD. There was no significant relationship between BMD at any site and dietary nutrient intake. Multiple regression analyses, using BMD as the dependent variable, identified running status, pubertal stage, fat mass and lean mass as significant determinants. When BMD/height was used, significant determinants in total body BMD were fat mass, pubertal stage and running status, while in the lumbar spine, only the latter two variables remained significant. In conclusion, body composition, physical activity and sexual maturity were identified as significant determinants of bone density during adolescence. Runners had significantly lower body fat than non-runners, but this did not interfere with hormonal cyclicity, and caused no detriment to their bone density. The results of this study are reassuring, since they indicate that sub-elite competitive athletics has no detrimental effect on bone mass accrual in adolescent females.

Trends in fertility patterns of women in rural Zimbabwe

To study changes over time in reproductive health and living conditions of women in a rural setting in Zimbabwe, 12 villages were selected at random in the Gutu district, Masvingo province. During two study periods in 1992 and 1993, 1,213 women of fertile age (15-44 years) were interviewed and examined. Median age at menarche was 15 years, with a decrease of 0.4 years from the oldest to the youngest age group. There has been no increase in the mean height of women, indicating no change in determinants of nutritional status of girls in childhood and adolescence. Younger women still marry at a median age of 19 years but prefer smaller families. Level of education is the main determinant for age at marriage and preferred family size. A low prevalence of primary (1%) as well as secondary infertility (4%) was found in spite of the currently reported high prevalence of sexually transmitted diseases in Zimbabwe.

Height, weight and menarcheal age of schoolgirls in Oslo--an update

Every fifth year since 1920 measurements of height and weight of the school-children in Oslo have been centrally processed. We present updates obtained for girls in 1980 and 1985, and in addition results on menarche from 1985. The slow but steady post-war increase in height seems to approach a plateau. For body weight the downward post-war trend has been reversed. Menarcheal age was close to the stable level of about 13.3 years observed since 1950. Regression analyses indicate a co-variation of weight development and menarche. Differences in height between city areas were small, while weight was clearly highest and menarcheal age clearly lowest in areas with the lowest average income.