Dietary Fat and Sports Activity as Determinants for Age at Menarche

Abstract

A prospective study (1985-1991) was conducted to evaluate the role of nutrition, physical activity, and other life-style factors for the age at menarche, a known breast cancer risk factor. In 1988-1989, a total of 261 girls, aged 8-15 years, from a nationwide representative nutrition and activity survey (1985-1988) responded additionally to a mailed questionnaire on personal maturation and anthropometric data, physical activity, and information about nutritional habits, measured by a short food-frequency questionnaire. All girls without menarche at the time of questionnaire mailing were observed for 2 years or until the event of menarche. At the end of the follow-up period, 79% of the girls had experienced menarche. The survey and questionnaire data were analyzed for their relation to age at menarche using Cox's proportional hazards method. After excluding participants with largely deviating measurements between survey and questionnaire, the increased energy-adjusted fat intake was associated with accelerated menarche (relative risk = 2.1; 95% confidence interval 1.1-4.0; lowest vs. highest quartile), while increased sports activity was associated with a delay in menarche (relative risk = 0.3; 95% confidence interval 0.1-0.5; lowest vs. highest quartile). Parameters of physical development such as body weight or body fatness were found to be predictors of menarche. The study provides evidence that dietary effects on breast cancer risk might be indirect by influencing hormonal events like the age at menarche.

Diet throughout childhood and age at menarche in a contemporary cohort of British girls

“…A large retrospective study of UK vegetarians in the 1990s found no difference in AAM between life-long vegetarians and those becoming vegetarian as adults (48) . Several other later studies which measured protein intake around the time of menarche found little evidence of an association (10)(11)(12)(13)(14)(15) .…”

Lifetime recreational exercise activity and risk of breast carcinoma in situ

“…4 High levels of moderate and vigorous physical activity before menarche may delay the onset of menses. 25,26 During a woman's reproductive years, strenuous exercise activity is associated with an increased likelihood of secondary amenorrhea, irregular or anovulatory menstrual cycles, and shortened luteal phases of the menstrual cycle. 27,28 These alterations in menstrual function have been associated with reduced levels of estradiol, progesterone, and follicle-stimulating hormone, particularly during adolescence.…”

Statistical modelling of breast cancer incidence and mortality rates in Scotland

“…It may well be that the alteration of eating patterns as a result of rationing in the wartime and immediate post-war period, and the subsequent influence on certain breast cancer risk factors probably produced by such changes (e.g. age at menarche; Merzenich et al, 1993) coupled with the introduction of the United Kingdom National Health Service in 1948 and the subsequent availability of cod liver oil, orange juice and milk formulate for all infants and young children, and school milk for school-age children, may be having some influence on the development of healthier girls and women. Such speculation could be addressed in a well-designed epidemiological study.…”