Data is required to test hypotheses regarding age of menopause and adolescent sports participation based on breast size:
Hypothesis 1: Women who are single/divorced will experience the menopause at an earlier age than women who are married/in a relationship.
Hypothesis 2: Sexually active women will experience a later menopause than their counterparts who do not have sex/have sex less frequently.
Hypothesis 3: Sports participation during adolescence is contingent upon female breast size/development.
For the first two hypotheses, maternal age of menopause will serve as the dependent variable, with marital status and sexual activity acting separate predictors. Control variables will include: socioeconomic status, whether a smoker or not (and frequency of such), BMI, reason for period stopping, age of first and last birth, amount of children, inter-birth interval, contraceptive use, HRT use, ethnicity, age of respondent, and age of first period. The purpose of this study is to assess the causation associated with marital status/sexual activity and age of menopause. While previous studies have found an association between being single/divorced and an earlier age of menopause, it is unclear whether people are single because they had the menopause earlier, or whether the menopause occurred earlier as a result of their marital status. If the latter is found, we will attempt to use evolutionary theory to explain the phenomenon, with a similar principle being applied to level of sexual activity.
The third hypothesis will investigate whether females with larger breasts participate in sports less frequently. Once again, we will analyse the results from within an evolutionary framework, utilising the mismatch hypothesis. Should women with larger breasts participate in sports less, then it may be that there is a trade-off between reproductive success and physical health; for, while larger breasts are positive for reproductive purposes, they may be hindering in regards to exercise and physical fitness. Here, sports participation serves as the dependent variable, with breast development being used as a predictor. Control variables include ethnicity, BMI, maternal socioeconomic status, gynoid lean and fat mass, smoking status, age at completion, and timing of first period.
All hypotheses will be tested using three separate event history models.