Dr Lauren Williams: Factors affecting weight change in mid-aged women.

This thesis describes research exploring factors that affect weight change in a population-based sample of mid-aged Australian women.
Two separate studies were conducted.

In Study One,
data from successive surveys of the Mid-age ALSWH cohort were used to explore patterns of weight change over a two-year period in a cohort of 14,100 women. Cross-sectional analysis using a linear regression model showed that body mass index tended to be higher in the late peri-menopause compared with other categories of menopause status. Prospective investigation of weight change and menopause transition showed that women who were peri-menopausal for two years gained slightly more weight (1.3 kg) than those who remained pre-menopausal (0.8 kg) over a two year period.

Study Two,
of the Weight Change at Menopause Study, involved a series of focus group discussions with menopausal women, aimed at identifying factors that the women believed influenced their body weight. Based on the findings, a 16-page survey was mailed to 1161 Mid-age ALSWH women who had experienced a change in menopausal status; 875 (77%) responded.
The 326 women who gained weight were compared with the 483 who avoided weight gain. While there was no significant difference between the two groups on dietary intake, there were several key differences in lifestyle and behavioural factors. The weight-gainers reported a higher frequency of hot flushes and night sweats than the non-gainers. The weight-gainers were more likely to attribute their weight gain to factors beyond their control, while non-gainers reported taking steps to control their weight. The weight–gainers were more likely than the non-gainers to be in full-time employment, to view their career as their main role in life, and to report that being under time pressure meant that they had increased energy intake in comparison with three years previously. The weight-gainers were also more likely to have quit smoking, and reported more dieting behaviour than the non-gainers and less vigorous physical activity.

In investigating both the prevalence and factors associated with weight gain in middle-aged women, these research findings have the potential to inform development of population-based strategies to prevent weight gain at this life stage.