Behavior-biological mismatch in metabolic health: Evidence from South Korean adults before, during, and after COVID-19 (KNHANES 2019-2022).

The physically active but metabolically healthy (PA-H) group declined during the pandemic and rebounded thereafter, while the PA-NH group increased from 31.2% to 34.0% over the study period.

• Data were drawn from 17,719 adults aged ≥19 years using the 2019-2022 Korea National Health and Nutrition Examination Survey (KNHANES).
• The pre-pandemic period was defined as 2019, during-pandemic as 2020-2021, and post-pandemic as 2022.
• PA-NH prevalence rose from 31.2% (2019) to 34.0% (2022).
• Temporal patterns were assessed using χ² tests and ANOVA.

Older adults had markedly higher odds of belonging to the PA-NH group compared to younger adults.

• Adults aged ≥70 years had an odds ratio of 7.30 for PA-NH membership compared to those aged 19-29 years.
• Age was identified as a determinant of PA-NH membership through multinomial logistic regression.
• Older adults were identified as a priority high-risk group for targeted post-pandemic public health strategies.

Women were less likely to belong to the PA-NH group compared to men.

• Sex was identified as a significant sociodemographic determinant of PA-NH membership in multinomial logistic regression.
• The finding was consistent across the pre-, during-, and post-pandemic periods examined.

Higher education reduced the odds of PA-NH membership relative to the PA-H group but increased them compared with the NPA-NH group.

• Education level was assessed as a sociodemographic determinant using multinomial logistic regression.
• The direction of the association with education differed depending on the reference group used in the comparison (PA-H vs. NPA-NH).
• This suggests a complex relationship between education, physical activity behavior, and metabolic health status.

Metabolic risk factors including hypertension and hypercholesterolemia rose despite recovery in physical activity levels after the pandemic.

• The persistence of elevated metabolic risk factors occurred even as PA levels rebounded in the post-pandemic period (2022).
• This pattern supports the concept of a 'behavior-biological mismatch' where behavioral improvements do not translate directly to metabolic health improvements.
• The finding was observed in the 2019-2022 KNHANES dataset of 17,719 Korean adults.

Participants were classified into four groups based on physical activity and metabolic health status: PA-H, NPA-H, NPA-NH, and PA-NH.

• PA-H: physically active and metabolically healthy.
• NPA-H: not physically active but metabolically healthy.
• NPA-NH: not physically active and metabolically unhealthy.
• PA-NH: physically active but metabolically unhealthy.
• Classification was applied to 17,719 adults aged ≥19 years across four survey years (2019-2022).