Small left ventricular size as a predictor for incident type 2 diabetes: insights from the UK biobank cardiovascular magnetic resonance substudy

BACKGROUND: Left ventricular (LV) concentric hypertrophy is common in diabetes patients, presenting as a relatively small LV size. However, studies have shown that a small LV size can also occur in prediabetic conditions without ventricular hypertrophy. We used data from the UK Biobank Cardiovascular Magnetic Resonance Substudy to assess whether a small LV size independently predicts incident type 2 diabetes. METHODS AND RESULTS: Small LV size was defined using indexed left ventricular end-diastolic volume (iLVEDV) values (< 56 mL/m² for females and < 57 mL/m² for males). The risk of small LV size for incident type 2 diabetes was assessed using adjusted Cox proportional hazards models. The non-linear relationship between iLVEDV and diabetes risk was evaluated using restricted cubic splines. This study included 35,422 participants, with an average age of 64 years, of whom 53.2% were females. Among the 35,422 participants, 947 (2.7%) had small LV size. During a median follow-up of 698 days, 304 cases of incident type 2 diabetes were recorded. Those with small LV size showed a significant association with increased risk of incident type 2 diabetes (adjusted hazard ratio HR, 2.36; 95% CI, 1.56-3.57). Subgroup analysis consistently supported this relationship across age, sex, hypertension, obesity, and genetic risk for type 2 diabetes. An L-shaped relationship between iLVEDV and diabetes risk was also observed. CONCLUSIONS: Small LV size is an independent predictor of incident type 2 diabetes, with a smaller LV size correlating with a higher risk of developing the condition, warranting further investigation.