Severe obesity with fewer comorbidities is more prevalent in older Japanese women than in older Japanese men: Novel findings from the K7Ps Study-9 (Preprint)

UNSTRUCTURED This study investigated sex- and age-related differences in severe obesity among 9 million Japanese adults aged 40–74 years using the National Database of Health Insurance Claims and Specific Health Checkups. Overall, obesity, severe obesity, and class 3 obesity were more common in men than in women. However, after age stratification, women aged ≥ 60 years showed a higher prevalence of severe obesity and women aged 70–74 years had a higher prevalence of obesity than men of the same age. Despite their higher prevalence of severe obesity, older women had lower waist circumference, serum triglyceride and HbA1c levels, lower usage of medications for hypertension and diabetes, and a lower prevalence of cardiovascular disease than older men. These findings suggest that severe obesity accompanied by fewer cardiometabolic comorbidities is more common in older Japanese women than in older Japanese men. This unique phenotype might partly contribute to the exceptional longevity of Japanese women and warrants further investigation in populations aged 75 years and older.