A survey of salt intake, blood pressure, and non-communicable disease risk factors in Viet Nam
While numerous epidemiological studies have reported evidence of an association between dietary salt intake and blood pressure, the majority of this evidence has come from developed countries; little is known about the influence of salt consumption in developing countries. Furthermore, in Viet Nam -- a country that has undergone a rapid economic and demographic transition in the past 10-20 years -- nation-wide statistics are scarce, and previous studies attempting to characterize non-communicable disease risk factors were limited by small sample sizes or a limited number of investigated risk factors. Using data from 14,706 participants in a 2009 Viet Nam national survey, this dissertation validates the use of mid-morning spot urine collections as a practical alternative to 24-hour urine collections for estimating salt intake, assesses the association of salt consumption with untreated blood pressure among Vietnamese adults, and presents contemporary, nationally representative prevalence statistics for non-communicable disease (NCD) risk factors among adults in Viet Nam. In 154 participants who provided spot and 24-hour urine collections, we observed a moderate correlation (rho = 0.34 - 0.35) between spot urine estimated and 24-hour measured salt consumption. Correlations were higher in women (rho = 0.39 - 0.40) than in men (rho = 0.30 - 0.31). In adjusted regression models, we observed no evidence of an association of salt consumption with untreated systolic blood pressure or prevalent hypertension at a national scale in Viet Nam. The associations did not differ in subgroups defined by age, smoking, or alcohol consumption; however, the association of salt consumption with untreated systolic blood pressure was stronger in urban residents than in rural residents (p-value for interaction of urban/rural status with salt consumption, p = 0.02). After incorporating sampling and post-stratification weights, the prevalence of NCD risk factors among Vietnamese adults aged 25-65 in 2009 was higher among those living in urban areas than those living in rural areas. The levels of hypertension awareness, treatment, and control were below those seen in other low- and low-middle income countries. Given recent economic and demographic changes, public health interventions should address NCD risk factors that will become more prominent as the population ages.