Usual Blood Pressure and Risk of New-Onset Diabetes
Background Reliable quantification of the association between blood pressure (BP) and risk of type 2 diabetes is lacking.
Objectives This study sought to determine the association between usual BP and risk of diabetes, overall and by participant characteristics.
Methods A cohort of 4.1 million adults, free of diabetes and cardiovascular disease, was identified using validated linked electronic health records. Analyses were complemented by a meta-analysis of prospective studies that reported relative risks of new-onset diabetes per unit of systolic blood pressure (SBP).
Results Among the overall cohort, 20 mm Hg higher SBP and 10 mm Hg higher diastolic BP were associated with a 58% and a 52% higher risk of new-onset diabetes (hazard ratio: 1.58; 95% confidence interval [CI]: 1.56 to 1.59; and hazard ratio: 1.52; 95% confidence interval: 1.51 to 1.54), respectively. There was no evidence of a nadir to a baseline BP of 110/70 mm Hg. The strength of the association per 20 mm Hg higher SBP declined with age and with increasing body mass index. Estimates were similar even after excluding individuals prescribed antihypertensive or lipid-lowering therapies. Systematic review identified 30 studies with 285,664 participants and 17,388 incident diabetes events. The pooled relative risk of diabetes for a 20 mm Hg higher usual SBP across these studies was 1.77 (1.53 to 2.05).
Conclusions People with elevated BP are at increased risk of diabetes. The strength of the association declined with increasing body mass index and age. Further research should determine if the observed risk is modifiable.
In 2011, type 2 diabetes affected 366 million people worldwide; this prevalence is estimated to increase to 552 million by 2030. Individuals with type 2 diabetes are at increased risk of major cardiovascular events, including ischemic heart disease, stroke, and heart failure. In a contemporary analysis of a U.K. primary care population, type 2 diabetes was associated with twice the risk of all-cause mortality and 3 times the risk of cardiovascular mortality relative to age- and sex-matched controls. Consequently, prevention of diabetes is critically important for reducing the burden of cardiovascular disease.
Although hypertension has long been recognized as an independent risk factor for fatal and nonfatal vascular events, the relationship between blood pressure (BP) and risk of new-onset diabetes is less clear. Elevated BP is associated with chronic inflammation and endothelial dysfunction, both of which appear to be mediators of diabetes risk. There is, therefore, a biological rationale to suspect that elevated BP may cause new-onset diabetes. However, among 30 cohort studies that have reported the association of BP and diabetes, 12 concluded that no such association is apparent, whereas the others reported a considerably variable strength of association (Online Table 1 http://content.onlinejacc.org/data/Journals/JAC/934520/07059_mmc1.docx). Moreover, even the largest previous cohorts have had limited power to investigate whether any observed positive association between BP and diabetes varied significantly by important patient features.
A detailed understanding of BP as a potential risk factor for diabetes will help us better understand and communicate risks with patients and can lead to more targeted prevention and management. We therefore undertook both an analysis of 4.1 million individuals free from diabetes and cardiovascular disease in a contemporary U.K. primary care population and a meta-analysis of existing prospective studies to reliably determine the association between BP and diabetes.
Abstract and Introduction
Abstract
Background Reliable quantification of the association between blood pressure (BP) and risk of type 2 diabetes is lacking.
Objectives This study sought to determine the association between usual BP and risk of diabetes, overall and by participant characteristics.
Methods A cohort of 4.1 million adults, free of diabetes and cardiovascular disease, was identified using validated linked electronic health records. Analyses were complemented by a meta-analysis of prospective studies that reported relative risks of new-onset diabetes per unit of systolic blood pressure (SBP).
Results Among the overall cohort, 20 mm Hg higher SBP and 10 mm Hg higher diastolic BP were associated with a 58% and a 52% higher risk of new-onset diabetes (hazard ratio: 1.58; 95% confidence interval [CI]: 1.56 to 1.59; and hazard ratio: 1.52; 95% confidence interval: 1.51 to 1.54), respectively. There was no evidence of a nadir to a baseline BP of 110/70 mm Hg. The strength of the association per 20 mm Hg higher SBP declined with age and with increasing body mass index. Estimates were similar even after excluding individuals prescribed antihypertensive or lipid-lowering therapies. Systematic review identified 30 studies with 285,664 participants and 17,388 incident diabetes events. The pooled relative risk of diabetes for a 20 mm Hg higher usual SBP across these studies was 1.77 (1.53 to 2.05).
Conclusions People with elevated BP are at increased risk of diabetes. The strength of the association declined with increasing body mass index and age. Further research should determine if the observed risk is modifiable.
Introduction
In 2011, type 2 diabetes affected 366 million people worldwide; this prevalence is estimated to increase to 552 million by 2030. Individuals with type 2 diabetes are at increased risk of major cardiovascular events, including ischemic heart disease, stroke, and heart failure. In a contemporary analysis of a U.K. primary care population, type 2 diabetes was associated with twice the risk of all-cause mortality and 3 times the risk of cardiovascular mortality relative to age- and sex-matched controls. Consequently, prevention of diabetes is critically important for reducing the burden of cardiovascular disease.
Although hypertension has long been recognized as an independent risk factor for fatal and nonfatal vascular events, the relationship between blood pressure (BP) and risk of new-onset diabetes is less clear. Elevated BP is associated with chronic inflammation and endothelial dysfunction, both of which appear to be mediators of diabetes risk. There is, therefore, a biological rationale to suspect that elevated BP may cause new-onset diabetes. However, among 30 cohort studies that have reported the association of BP and diabetes, 12 concluded that no such association is apparent, whereas the others reported a considerably variable strength of association (Online Table 1 http://content.onlinejacc.org/data/Journals/JAC/934520/07059_mmc1.docx). Moreover, even the largest previous cohorts have had limited power to investigate whether any observed positive association between BP and diabetes varied significantly by important patient features.
A detailed understanding of BP as a potential risk factor for diabetes will help us better understand and communicate risks with patients and can lead to more targeted prevention and management. We therefore undertook both an analysis of 4.1 million individuals free from diabetes and cardiovascular disease in a contemporary U.K. primary care population and a meta-analysis of existing prospective studies to reliably determine the association between BP and diabetes.