Abstract
Objective: To investigate the impact of changes in physical activity from young adulthood (ages 20–35 years) to middle age (ages ≥35 years) on the prevalence of obesity, insulin resistance, and diabetes.
Research design and methods: Data were analyzed from 1,395 participants in the Midlife in the United States (MIDUS) study, including biomarker subsamples. Participants reported their physical activity levels during young adulthood and currently (≥ 20 min, three times per week). Participants were categorized as persistently active, increased, decreased, or persistently inactive. Obesity was defined as body mass index (BMI) ≥ 30 kg/m², insulin resistance by HOMA-IR ≥ 2.8, and diabetes by self-reported diagnosis. Multivariable logistic regression was used to assess associations.
Results: Participants with decreased or persistently low physical activity levels were significantly more likely to have obesity (OR 2.29 and OR 2.03, respectively), insulin resistance (OR 1.88 and OR 1.79, respectively), and diabetes (OR 1.79 and OR 1.73, respectively) compared to persistently active subjects. After adjusting for covariates, including age, income, and alcohol consumption, increased activity did not exhibit a significant protective effect compared to persistent activity.
Conclusions: A decline in physical activity after the age of 35 years is associated with higher risks of obesity, insulin resistance, and diabetes. Health promotion programs targeting the maintenance of regular physical activity in adulthood may reduce these risks. Further longitudinal studies are needed to confirm these findings and address limitations, including sample diversity and missing data.
Keywords
Diabetes, Exercise, Insulin resistance, Obesity, Physical activity