Aims/hypothesis: Sex differences in macrovascular disease, especially in stroke, are observed across studies of epidemiology. We studied a large sample of patients with type 2 diabetes to better understand the relationship between glycaemic control and stroke risk.
Methods: We prospectively investigated the sex-specific association between different levels of HbA(1c) and incident stroke risk among 10,876 male and 19,278 female patients with type 2 diabetes.
Results: During a mean follow-up of 6.7 years, 2,949 incident cases of stroke were identified. The multivariable-adjusted HRs of stroke associated with different levels of HbA(1c) at baseline (HbA(1c) <6.0% [<42 mmol/mol], 6.0-6.9% [42-52 mmol/mol] [reference group], 7.0-7.9% [53-63 mmol/mol], 8.0-8.9% [64-74 mmol/mol], 9.0-9.9% [75-85 mmol/mol] and ≥10.0% [≥86 mmol/mol]) were 0.96 (95% CI 0.80, 1.14), 1.00, 1.04 (0.85, 1.28), 1.11 (0.89, 1.39), 1.10 (0.86, 1.41) and 1.22 (0.92, 1.35) (p for trend = 0.66) for men, and 1.03 (0.90, 1.18), 1.00, 1.09 (0.94, 1.26), 1.19 (1.00, 1.42), 1.32 (1.09, 1.59) and 1.42 (1.23, 1.65) (p for trend <0.001) for women, respectively. The graded association between HbA(1c) during follow-up and stroke risk was observed among women (p for trend = 0.066). When stratified by race, whether with or without glucose-lowering agents, this graded association of HbA(1c) with stroke was still present among women. When stratified by age, the adjusted HRs were significantly higher in women older than 55 years compared with younger women.
Conclusions/interpretation: The current study suggests a graded association between HbA1c and the risk of stroke among women with type 2 diabetes. Poor control of blood sugar has a stronger effect in diabetic women older than 55 years.