National and subnational mortality effects of metabolic risk factors and smoking in Iran: a comparative risk assessment

Abstract

BackgroundMortality from chronic diseases has increased in Iran. Our aim was to estimate the effects of smoking and high systolic blood pressure (SBP), fasting plasma glucose (FPG), total cholesterol (TC), and body-mass index (BMI) on mortality and life expectancy, nationally and subnationally, using representative data and comparable methods. MethodsWe used data from the Non-Communicable Disease Surveillance Survey to estimate means and standard deviations for the metabolic risk factors. Lung cancer mortality was used to measure cumulative exposure to smoking. We used data from the death registration system to estimate age-specific, sex-specific, and disease-specific numbers of deaths in 2005, adjusted for incompleteness using demographic methods. We used systematic reviews and meta-analyses of epidemiological studies to obtain the effect of risk factors on disease-specific mortality. We estimated deaths and life expectancy loss attributable to risk factors using comparative risk assessment framework. FindingsIn 2005, high SBP was responsible for 41 000 (95% CI 38 000–44 000) deaths in men and 39 000 (36 000–42 000) deaths in women in Iran. High FPG, BMI, and TC were responsible for about a third to a half of deaths attributable to SBP in men and/or women. Smoking was responsible for 9000 deaths among men and 2000 among women. If SBP were reduced to optimal levels, life expectancy at birth would increase by 3·2 years (2·6–3·9) in men and 4·1 years (3·2–4·9) in women; the life expectancy gains ranged from 1·1 to 1·8 years for TC, BMI, and FPG. SBP was also responsible for the largest number of deaths in every region, with age-standardised attributable mortality ranging from 257 to 333 deaths per 100 000 adults in different regions. InterpretationManagement of blood pressure through diet, lifestyle, and pharmacological interventions should be a priority in Iran. Interventions for other metabolic risk factors and smoking can also improve population health. FundingNone.