Association between opium consumption and sarcopenia in middle-aged and older adults: findings from the Fasa Adults Cohort Study (FACS).

Sarcopenia, a condition linked to disability, frailty, and mortality, is influenced by multiple lifestyle and metabolic factors, but its association with opium consumption has not been evaluated. We conducted a cross-sectional analysis of adults aged 35–70 years in the Fasa Adult Cohort Study (FACS). Sarcopenia was defined as skeletal muscle mass index (SMI) in the lowest two quantiles (lowest 40%), and opium use, including dose, was measured using standardized questionnaires. Logistic regression models estimated adjusted odds ratios (ORs) and 95% confidence intervals (CIs), with subgroup analyses performed across demographic, dietary, and clinical factors. Opium use was associated with 76% higher odds of sarcopenia (OR = 1.76, 95% CI 1.31–2.36, p < 0.001). The association was consistent across physical activity, socioeconomic status, and protein intake strata, but significant only in males (OR = 1.69, 95% CI 1.22–2.34, p = 0.002). It was also evident among participants with low dietary inflammatory index, low alcohol intake, and without major chronic conditions. Within users, higher opium dose showed a modest dose-related relationship with sarcopenia risk (OR = 1.01 per mesghal/year, 95% CI 1.00–1.01, p = 0.040). These findings demonstrate a strong and independent association between opium use and sarcopenia, especially in men and otherwise healthy individuals, underscoring the need for routine muscle assessment in opium users and integration of sarcopenia prevention into cessation strategies.