A survey of salt intake, blood pressure, and non-communicable disease risk factors in Viet Nam

Thesis (Ph.D.)--University of Washington, 2014While 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