Operationalization, characterization and validation of a healthy lifestyle index in 35 LMICs

BACKGROUND: For low- and middle-income countries (LMICs), there is no comprehensive and valid index reflecting overall lifestyle. This study aimed to operationalize, characterize, and validate a healthy lifestyle index (HLI), based on the World Health Organization (WHO) recommendations. METHODS: We used cross-sectional, complete-case data from individual-level, nationally representative surveys among non-pregnant adults in 35 LMICs, applying the WHO STEPwise approach to NCD risk factor surveillance (2009-2019; N = 125,607). The HLI was constructed based on WHO recommendations for fruit and vegetable intake, physical activity, smoking, and alcohol intake (unhealthiest = 0 points; healthiest = 16 points). We calculated the distributions of the HLI and its subcomponents across socio-demographic and geographic strata, accounting for the survey design and each country's World Bank population estimate. Partial Spearman correlations were calculated for the HLI with its subcomponents and cardio-metabolic risk markers. RESULTS: In this study (females: 51%, median age: 35.4 years), median HLI-score was 10.3 (interquartile range: 8.2-12.3), being highest in females (versus males) and low-income countries (versus middle-income countries). Twenty-two percent had at least five servings of fruits and vegetables per day (males: 20%, females: 24%); 82% exercised at least 600 MET-min/week (males: 87%, females: 78%); 69% never smoked (males: 40%, females: 97%); 64% were alcohol abstainers (males: 50%, females: 78%). Correlations of the HLI with its subcomponents were moderate and positive, ranging between r = 0.35 and r = 0.64; correlations with cardio-metabolic risk markers were weak, ranging between r = |0.02| and r =|0.12|. CONCLUSIONS: The majority of adults in LMICs appear to live a healthy lifestyle, particularly women and individuals in low-income countries. Low fruit and vegetable intakes are a major concern. The HLI shows good content but poor construct validity. KEY MESSAGES: • There is an urgent need for interventions to promote fruit and vegetable consumption in LMICs. • The HLI is suitable to monitor lifestyles in LMICs on individual-, country- and WHO region-level.