Risk factors for non-communicable disease in Vietnam : estimates of prevalence, and issues in measurement

Background and Aims Non-communicable disease (NCD) is the leading cause of death worldwide. In Vietnam, there has been an increase in morbidity and mortality rates in recent decades, but data on NCD risk factors are limited. The principal aim of this thesis was to provide national estimates of the mean levels or prevalence of NCD risk factors. The secondary aim was to investigate issues in the measurement of these risk factors, and in the analysis and interpretation of data collected and reporting of results. Methods A population-based survey was conducted during 2009‚Äöv†v¿10 using the WHO STEPwise approach to surveillance of risk factors for NCDs‚ÄövÑvp (STEPS) methodology. Participants aged 25‚Äöv†v¿64 years were selected from eight provinces representing the eight ecological and geographical regions of Vietnam. Of the 22,940 eligible subjects selected by stratified multi-stage cluster sampling, 14,706 (64%) participated. National estimates of eight NCD risk factors are presented in the first of five studies, and the other four studies provide more detailed information on tobacco smoking, alcohol use, physical activity (PA) and fruit/vegetable intake. Results Study 1 provides national estimates of eight NCD risk factors. Notable findings were sex-differences in proportions of current smokers (men 57.7%, women 1.7%), binge drinkers (men 25.1%, women 0.6%), active people (men 52.0%, women 41.1%), and hypertension (men 18.5%, women 10.2%). Mean levels of fruit/vegetable intake (2.8 serves/day), BMI (21.1) and blood cholesterol (5.6 mmol/L), and prevalence of diabetes (2.6%), were similar for men and women. The correlations between the summary values for each province were generally plausible, but with some anomalous findings due to the characterisation of smoking and hypertension by STEPS protocols. More detailed information on tobacco use is presented in study 2. Male ever-smokers commenced smoking at a median age of 19 years (women 20 years) and smoked a median of 10 cigarettes/day (women 6 cigarettes/day). For men, the proportion of current daily smokers peaked in the 1965‚Äöv†v¿69 birth cohort and has declined in more recent cohorts. For women, the proportion of current daily smokers has declined in successive cohorts after the 1950‚Äöv†v¿54 cohort. Study 3 provides more detailed information on alcohol use. Almost 60% of men but only 4% of women consumed alcohol during the last week. Nearly 40% of men were hazardous/harmful users. Gains in model calibration and subject discrimination from information on quantities of 'standard drinks' were minor after the contribution from binary responses to questions on whether or not alcohol had been consumed during the reference period. Study 4 provides more detailed information on domain-specific and overall PA. Approximately 70% met WHO recommendations for PA. Most PA was from work activity, which was higher in rural areas and varied by season. One-in-six provided unrealistically high PA values. Box-Cox transformation was the most successful method of reducing the influence of large values, but values scaled to the average Vietnamese energy intake produced the strongest correlations with pathophysiological outcomes. More detailed information on fruit/vegetable consumption is presented in study 5. Nearly 80% reported having less than five servings of fruit/vegetables daily in a typical week. The measurements were plausibly correlated with socioeconomic factors in individual-level analyses, and with provincial characteristics in aggregate analyses. Conclusions This thesis provides the first nationally-representative estimates of mean levels or prevalence of NCD risk factors in Vietnam. These data suggest that efforts to limit future growth in NCDs should be targeted at reducing tobacco smoking and binge drinking by men, encouraging physical activity, and increasing consumption of fruit and vegetables. These interventions should take account of the sex-, urban-rural and regional differences in these risk factors that were identified in this thesis. The results from this research could help to strengthen the implementation Programme of Prevention and Control of Certain Non-communicable Diseases for the Period 2010vîvÑ‚â†20 in Vietnam. In addition, the findings from the extensive assessment of the application of the STEPS instrument in Vietnam in respect of the measurement of behavioural risk factors, and the analysis, interpretation and reporting of the results, should be of value for other investigators using the instrument and for other users of data.