Time-cumulated blood pressure exposure and incident impairment of glucose tolerance and diabetes mellitus

BACKGROUND With the marked increase in the prevalence of diabetes mellitus, it was the purpose of our study to assess a potential association of time-cumulated exposure to systolic (CumSBP) and of diastolic blood pressure (CumDBP) with onset of impaired glucose tolerance and diabetes mellitus. METHODS The prospective investigation included participants of the longitudinal Kailuan Study with three baseline examinations in 2006-2007, 2008-2009 and 2010-2011, re-examination in 2012-2013, and no diabetes mellitus at baseline. Cumulative blood pressure (BP) was calculated as cumBP = [(BP1 + BP2)/2 × time1-2] + [(BP2 + BP3)/2 × time2-3]. Based on cumSBP, the study population was stratified into four groups (cumSBP < 480mmHgxyear;n = 15,339; 480mmHgxyear ≤ cumSBP < 520mmHgxyear;n = 7214; 520mmHgxyears ≤ cumSBP < 560mmHgxyears;n = 5675; and cumSBP ≥ 560mmHgxyears;n = 10,576). RESULTS After adjusting for demographic, anthropomorphic, biochemical, socioeconomic and lifestyle parameters and as compared with the first group, the second, third and fourth group showed a significantly higher incidence of diabetes (P-trend < 0.001;hazard ratio (HR);95% confidence interval (CI):1.28(1.08,1.51),1.54(1.29,1.84), and 2.33(1.98,2.73), respectively), higher incidence of impairment of glucose tolerance (P-trend < 0.001;HR;95% CI1.17(1.02,1.33), 1.43(1.25,1.64), and 2.09(1.85,2.37), respectively), and higher incidence of diabetes developing out of an impairment of glucose tolerance (P-trend < 0.001;HR;95% CI:1.22(0.97,1.54),1.47(1.16,1.86), and 2.01(1.62,2.50), respectively). An increase in cumSBP by 10 mmHg/year or an increase in cumDBP by 5 mmHg/year was associated with a hazard ratio of incident diabetes of 1.04 (95% CI:1.03,1.04) and 1.02(1.02,1.03), respectively, with a hazard ratio of incident impairment of glucose tolerance of 1.04(95% CI:1.03,1.04) and 1.03(95% CI:1.02,1.03), respectively, and with a hazard ratio of incident diabetes developing from impairment of glucose tolerance of 1.04(95% CI:1.03,1.04) and 1.03(95% CI:1.02,1.03), respectively. CONCLUSIONS Time-cumulated exposure to elevated blood pressure was significantly associated with an elevated incidence of impaired glucose tolerance and diabetes.