Foods, Mediterranean diet, and risk of multimorbidity: results from a large population-based cohort study

Multimorbidity has posed growing global health burdens, yet evidence on modifiable dietary risk factors remains limited. To explore the dietary factors influencing multimorbidity risk, a longitudinal study was conducted in the UK Women's Cohort.

The cohort initiated from 1995 to 1998 has recruited 35,372 women aged 35-69 years at baseline. Daily consumption of foods and a modified Mediterranean diet was evaluated based on a validated food frequency questionnaire with 217 items. Charlson comorbidity index (CCI) was used to assess multimorbidity based on diagnostic ICD codes from Hospital Episode Statistics. Associations between diet and multimorbidity were estimated using Cox's proportional hazards models. Subgroup analyses stratified by age at baseline and body mass index were additionally explored.

During 486,656 person-years of follow-up (mean 19.7 years), 7,516 of 24,703 participants (30.4%) developed incident multimorbidity. Compared with women with low adherence to Mediterranean diet, those with moderate or high adherence had 6% (hazard ratio = 0.94, 95% confidence interval: (0.89, 0.99)) or 14% (0.86 (0.80, 0.92)) lower risk of multimorbidity in the fully-adjusted models, respectively. Increased risk of multimorbidity was observed to be associated with each additional 10 g/MJ intake of processed meat (1.60 (1.37, 1.87)), red meat (1.19 (1.12, 1.26)), and total meat (1.12 (1.08, 1.17)). Above associations remained in subgroup analyses stratified by age at baseline or body mass index (BMI), except in the subgroup aged ≥ 60 years where the association between adherence to Mediterranean diet and risk of multimorbidity was attenuated significantly. Additionally, there was no significant evidence on effect modification of age at baseline or BMI on the dietary factors (all P-interaction > 0.05).

Adherence to Mediterranean diet was inversely, but consumption of meat especially processed meat was positively, associated with risk of multimorbidity. These modifiable dietary factors represent promising prevention targets, warranting further investigation in diverse populations.