**Background:** Non-communicable disease multimorbidity (NCD-MM), defined as the coexistence of two or more chronic NCDs, is a growing concern among ageing populations, particularly in low-income and middle-income countries (LMICs) like India. While evidence from high-income countries shows that multimorbidity affects a large proportion of older adults, research in India is still nascent. Sex and gender differences in multimorbidity are understudied in LMICs, despite known differences in disease-specific life expectancy, health behaviours, and clinical presentations. This study aimed to examine sex differences in NCD-MM prevalence, associated risk factors, and adverse health outcomes among adults aged 45+ in India using nationally representative data.
**Methods:** Data were drawn from the Longitudinal Ageing Study in India (LASI) wave 1 (2017-2018), a large-scale nationally representative survey. The analytic sample included 59,073 individuals aged 45+ (27,343 men and 31,730 women) with complete biomarker and socio-demographic data. NCD-MM was defined as the presence of two or more long-term chronic NCDs from a list of 25 self-reported and 2 measured conditions (hypertension and depression). Additional measures included complex multimorbidity (3+ conditions), physical-mental multimorbidity, mental-only multimorbidity, and physical-only multimorbidity. Adverse health outcomes assessed were limitations in activities of daily living (ADL), instrumental ADL (IADL), self-rated poor health (SRPH), and hospitalisation in the past 12 months. Covariates included age, education, marital status, working status, living arrangement, MPCE quintile, religion, caste, place of residence, physical activity, BMI, smoking, chewing tobacco, and alcohol consumption. Descriptive statistics, bivariate analyses, and multivariable logistic regression were used, including interaction terms to compute female-to-male ratios of odds ratios (RORs).
**Key Results:** Overall, the prevalence of NCD-MM was significantly higher among women (42.7%, 95% CI: 42.1% to 43.2%) than men (38.9%, 95% CI: 38.4% to 39.5%) (p<0.001). The most prevalent NCDs in both sexes were hypertension (31.6% men vs 31.1% women), depression (24.4% vs 29.9%), gastrointestinal issues (18.7% vs 18.0%), and diabetes (11.93% vs 11.92%). The greatest sex difference (11%) was observed in physical-mental multimorbidity among those aged 75+ (31.2% women vs 20.1% men). NCD-MM prevalence increased with age and was higher among widows (48.5%) than widowers (44.8%). Adjusted analyses showed that overweight/obesity was associated with 10% greater odds of NCD-MM in women compared with men (ROR: 1.10, 95% CI: 1.01 to 1.20). Prior history of chewing tobacco conferred 42% greater odds in women (ROR: 1.42, 95% CI: 1.12 to 1.80). Currently working women (ROR: 1.29, 95% CI: 1.11 to 1.50) and formerly working women (ROR: 1.24, 95% CI: 1.06 to 1.44) had higher odds of NCD-MM relative to men. Widowed women had 16% greater odds, and divorced/separated women had 28% greater odds compared with men. The effect of NCD-MM on ADL and IADL limitations was greater in men (12% and 7% greater relative increase, respectively), while the effect on hospitalisation was 14% greater in women.
**Clinical Implications:** This study provides robust evidence of significant sex differences in NCD-MM among older Indian adults, with women bearing a higher burden overall and for specific risk factors. The findings underscore the need for sex-sensitive screening and management strategies in primary care, particularly targeting modifiable risk factors like overweight/obesity and chewing tobacco use in women. The differential impact of multimorbidity on functional outcomes (worse in men) and hospitalisation (worse in women) suggests that clinical care and health system planning should account for these sex-specific patterns. The high prevalence of physical-mental multimorbidity in older women highlights the importance of integrating mental health services into chronic disease management. Health systems must respond to these patterns to redress inequities, with upstream interventions such as tobacco taxation and obesity prevention potentially yielding benefits across multiple morbidities. Further research is needed to explore state-level variations and the intersectionality of socio-demographic factors driving these sex differences.