The interplay between healthy lifestyle and body mass index in metabolic syndrome

Abstract The prevalence of metabolic syndrome (MS) tends to increase as body mass index (BMI) increases. However, the interplay between BMI and overall healthy lifestyle in MS remains unclear. We aimed to examine the association between healthy lifestyle and MS in BMI categories. Data comprised participants aged 30-64 years from the Healthy Finland Survey representing the Finnish adults (n = 2027). Information was collected through health examination measurements, blood sampling and questionnaires in 2023. Healthy Lifestyle Score (HLS) was defined as: 1) vegetables and fruits several times/day; 2) adherence to physical activity recommendations; 3) sufficient sleep duration; 4) no current daily smoking; 5) no risky alcohol drinking. Total score ranged 0-5; categorized as 0-2 (unhealthiest), 3, 4-5 (healthiest). MS was defined as exceeding risk limit in ≥ 3 of the following conditions: waist circumference, fasting glucose, triglycerides, blood pressure and HDL-cholesterol. BMI (kg/m2) was categorized as normal weight (<25), overweight, and obesity (≥ 30). Weighted prevalence and 95% confidence intervals (CIs) stratified by sex were calculated considering sampling design and non-response. In both sexes, the prevalence of MS was lowest in those with normal weight and healthiest lifestyle (men 7%; 95% CI 2-11; women 9%; 6-13) and highest in those with obesity and unhealthiest lifestyle (m 86%; 80-92; w 67%; 56-78). In men, the prevalence of MS decreased within each BMI class as HLS scores increased, but the difference between healthiest and unhealthiest lifestyle was greatest in those with normal weight (7% vs. 26%) and lowest in those with obesity (71% vs. 86%). In women, the differences were greatest among those with overweight. Obesity and unhealthy lifestyle together form a major risk factor for MS. Differences in the prevalence of MS according to lifestyle were evident especially in men with normal weight or overweight, but decreased when the obesity threshold was exceeded. Key messages • Obesity is strongly linked to the high prevalence of metabolic syndrome but maintaining a healthy lifestyle is important regardless of body mass index. • The results indicate the importance of multifaceted prevention influencing lifestyle factors and supporting weight management to enhance the cost-effective prevention of metabolic risk accumulation.