Association between lifestyle changes and metabolic syndrome: a prospective cohort study in middle-aged Koreans.

The prevalence of metabolic syndrome increased from baseline to follow-up in the study cohort.

• MetS prevalence rose from 15.3% at baseline (2017-2019) to 19.6% at follow-up (2020-2022).
• The study included 1436 adult individuals aged 30-59 years in a community-based, prospective cohort design in South Korea.
• MetS was determined according to established diagnostic criteria.

Insufficient physical activity at follow-up was significantly associated with metabolic syndrome.

• OR=1.42, 95% CI 1.06 to 1.92 for insufficient physical activity at follow-up.
• This was identified as a cross-sectional association at the follow-up time point.
• The association was statistically significant.

Poor sleep quality at follow-up was significantly associated with metabolic syndrome.

• OR=1.37, 95% CI 1.02 to 1.84 for poor sleep quality at follow-up.
• Sleep quality was one of five key lifestyle factors examined as secondary outcomes.
• The association was statistically significant.

Long-term unhealthy physical activity behaviour was associated with an increased risk of metabolic syndrome.

• OR=1.57, 95% CI 1.03 to 2.39 for long-term unhealthy physical activity patterns.
• Lifestyle change patterns were categorised into four groups based on stability between baseline and follow-up assessments.
• This finding indicates that persistent, rather than transient, insufficient physical activity carries elevated MetS risk.

Long-term poor sleep quality behaviour was associated with an increased risk of metabolic syndrome.

• OR=1.50, 95% CI 1.01 to 2.24 for long-term unhealthy sleep quality patterns.
• This was identified from analysis of lifestyle change pattern categories across the two time points.
• The association was statistically significant.

Unfavourable changes in sleep duration were significantly associated with incident metabolic syndrome in Poisson regression analyses.

• Rate ratio=1.74, 95% CI 1.02 to 2.95 for unfavourable changes in sleep duration.
• This was the only lifestyle change pattern significantly associated with incident MetS in Poisson regression analyses of incident cases.
• No other lifestyle change patterns, including behaviours that improved or worsened over time, showed significant associations with incident MetS.

Smoking and alcohol consumption were not significantly associated with metabolic syndrome in this study.

• No meaningful associations were identified for smoking and alcohol consumption.
• These were among the five key lifestyle factors examined alongside physical activity, sleep quality, and sleep duration.
• Alcohol consumption and smoking were described as 'non-significant lifestyle factors' in this cohort.