A cohort study on the relationship between blood pressure levels and the mortality of cerebro-cardiovascular diseases in Guangzhou workers

OBJECTIVE: To study the relative risk (RR) of mortalities of cerebro-cardiovascular diseases (CVD) in Guangzhou workers with hypertension. METHOD: Prospective cohort study was conducted in 78,379 workers, aged >or= 35, from 399 factories. Cox regression model were mainly used for data analysis. RESULTS: (1) There were 48,705 male and 29,674 female workers in the cohort. All workers were followed-up for 8 years. 363 CVD deaths (male 305, female 58) mainly died of stroke, coronary heart disease and hypertension. The crude mortalities were 78.58/100,000 person years in male and 24.55/100,000 person years in female. (2) Compared with the optimal or normal blood pressure (ONBP), the RR (95%) of CVD deaths with high blood pressure (HBP) were 6.19 (4.85 - 7.91) in male and 2.78 (1.59 - 4.85) in female. In male, compared with ONBP, the RR of CVD deaths without illness but with 1st-grade HBP at baseline, and of those suffered non-CVD but with 1st-grade HBP at baseline, and of those suffered CVD with 2nd-grade HBP at baseline were 3.98, 3.25 and 3.15 respectively (P < 0.01). (3) After stratifying of age, smoking, drinking, educational levels and occupational exposure, the RR of CVD deaths was higher in those who were younger, or ever-smoking, non-drinking, higher educational level, exposed to occupational hazards and with hypertension. CONCLUSION: There is relationship between BP levels and CVD mortality. High BP may affect CVD deaths at younger age. Comprehensive measures should be used to reduce the risk of CVD deaths.