Trajectories and determinants of weight gain in two cohorts of young adult women born 16 years apart

Abstract

Background The aims were to compare: (1) baseline weights and weight gain trajectories; (2) sociodemographic, behavioural and health characteristics driving weight gain; and (3) estimated average weight in 20 years’ time, in two cohorts of young women. Methods Data were from 16066 participants in two population-based cohorts of young adult women, born in 1973–78 (“GenX”) and 1989–95 (“millennials”). Weight was reported at baseline (age 18–23 in both cohorts) and 4 years later. High weight gain was defined as >2.5% per year. Data were analysed in 2020. Results Women born in 1989–95 were almost 4 kg heavier at age 18–23 and gained weight over 4 years 1.7 times faster than those born in 1973–78. Prevalence of high weight gain was 34.2% in the 1989–95 cohort and 24% in the 1973–78 cohort. In both cohorts, older age, higher education and high physical activity were associated with lower odds of high weight gain, and more hours in paid work, poorer self-rated health and higher baseline BMI were associated with higher odds of high weight gain. Five factors (outer regional areas, one child, ex or current smoker, high stress and depression) were determinants of high weight gain in the 1989–95 cohort, but not in the 1973–78 cohort. Based on average weight at age 21 and annual percentage weight gain, we estimate that women born in 1989–95 will, on average, be 16.7 kg heavier at age 41 (93.2 kg), than women in the 1973–78 cohort (76.5 kg). Conclusion High weight gain was evident in every sociodemographic group in both cohorts but most evident in millennial women with high levels of stress and depression. Without effective weight gain prevention strategies we estimate that more than 50% of the millennial women will be in the obese BMI category in 20 years. This will have serious economic, health and societal consequences.

The trajectory of body mass index in women with PCOS in two cohorts of Australian women

“…Of concern, the rate of gain in BMI was greater in women in the cohort born 1989-95 than in the cohort born 1973-1978 at the same ages. This difference between the two cohorts has previously been reported for the two cohorts overall [9,10], but this analysis shows that the average annual increase in BMI is even higher for women with PCOS than for other women.…”

“…We used the slope of the model to estimate the average annual increase in BMI in women who reported a diagnosis of PCOS and in women who did not report the diagnosis. The model was adjusted using covariates that have been shown to be related to the gain in BMI over time or hypothesised to be potential in uences: stress levels, self reported physical activity level, alchohol use, smoking status, marital status, highest level of education achieved, ability to manage on income, self-rated health status and baseline BMI [9]. We did not include a measure of dietary habits as we did not have reliable data from the surveys.…”

Obesity Fact Sheet in Korea, 2020: Prevalence of Obesity by Obesity Class from 2009 to 2018

“… 16 A study of two cohorts of young adult women born in 1973–1978 and 1989–1995 revealed high weight gain in all sociodemographic groups, but this was most evident in millennial women born in 1989–1995 with high levels of stress and depressive mood. 17 Meanwhile, a great deal of research has suggested that there is a strongly positive association between obesity and the prevalence of some metabolic complications; however, some literature suggests that the relationship between obesity and metabolic risk may become weaker or stronger with age depending on the risk factor in question. 18 Therefore, prevention and treatment of obesity in young adults is a global public health priority to decrease the risk of related chronic diseases and mortality in later adulthood.…”

Policies and healthcare to support preconception planning and weight management: optimising long-term health for women and children

“…4 Young adult women are experiencing rapid weight gain that increases over time; a national longitudinal study of two population cohorts in Australia reported that women born 1989-95 were heavier and gaining weight faster that those of an older cohort (born 1973-78). 5 This rapidly changing, global trend in obesity in women of reproductive age, associated with inequity, and its impact on the health of women and their children, makes policies, health promotion, and services enabling good preconception health (including interconception or between pregnancies) a global public health priority. 6,7 However, it is important to recognise that weight sits within a socio-ecological framework, and Key points (continued) Optimising health through preconception planning and weight management all women (e.g.at schools, pharmacies, contraception clinics).…”