Does the Combination of Abdominal Obesity and Vitamin D Deficiency Increase the Risk of Death in Individuals Aged 50 or Older? Evidence From the ELSA Study

AIMS: Despite the known association between abdominal obesity (AO) and vitamin D deficiency, it remains unclear whether this combination is associated with higher mortality risk. We investigated whether the coexistence of AO and vitamin D deficiency elevates the risk of death. MATERIALS AND METHODS: Five thousand, five hundred twenty participants from the ELSA Study, aged ≥ 50 years, were followed for 6 years. AO was defined by waist circumference (> 102 cm for men and > 88 cm for women). Vitamin D levels, measured via serum 25-hydroxyvitamin D [25(OH)D] concentrations, were categorised as sufficient (≥ 50 nmol/L), insufficient (30-50 nmol/L), and deficient (< 30 nmol/L). At baseline, participants were classified according to AO (non-abdominal obesity [NAO] and AO) and 25(OH)D status (sufficiency [VDS], insufficiency [VDI], and deficiency [VDD]), creating six groups: NAO/VDS, NAO/VDI, NAO/VDD, AO/VDS, AO/VDI, and AO/VDD. Cox regression models adjusted for sociodemographic, behavioural, and clinical characteristics estimated mortality risk. RESULTS: The NAO/VDI and NAO/VDD groups were associated with a 91% (HR = 1.91; 95% CI: 1.37-2.66) and 81% higher risk of death (HR = 1.81; 95% CI: 1.25-2.62), respectively. The AO/VDS and AO/VDI groups had a 47% (HR = 1.47; 95% CI: 1.02-2.14) and 50% higher mortality risk (HR = 1.50; 95% CI: 1.01-2.23), respectively, compared to the NAO/VDS group. The highest mortality risk was observed in the AO/VDD group (HR = 2.23; 95% CI: 1.50-3.33). CONCLUSIONS: AO combined with 25(OH)D deficiency increases mortality risk in older adults. Early identification and management of these conditions could reduce this risk.