Fruit and vegetable consumption in Vietnam, and the use of a 'standard serving' size to measure intake.

The aims of the present study were to provide nationally representative data on fruit and vegetable consumption in Vietnam, and to assess the accuracy of the reported numbers of 'standard servings' consumed. Data analysed were from a multi-stage stratified cluster survey of 14 706 participants (46·5 % males, response proportion 64·1 %) aged 25-64 years in Vietnam. Measurements were made in accordance with the WHO STEPwise approach to surveillance of non-communicable diseases (STEPS) protocols. Approximately 80 % of Vietnamese people reported having less than five servings of fruit and vegetables daily in a typical week. Fruit and vegetable intake reported in 'standard serving' sizes was positively correlated with levels of education completed and household income (P<0·001 for trend). The correlations between summary values for each province reflect some known demographic, geographical and climatic characteristics of the country. For example, provinces at higher latitude had higher mean servings of vegetables (r 0·90), and provinces with higher proportions of urban population had higher mean servings of fruit (r 0·40). In conclusion, about eight in ten Vietnamese people aged 25-64 years did not meet WHO recommendations for daily consumption of at least five servings of fruit and vegetables. On the basis of the consistency of the data collected with other estimates and with physical and demographic characteristics of the country, the WHO STEPS instrument has construct validity for measuring fruit and vegetable intake, but with two issues identified. The issues were seasonal variation in reporting and a limitation on the usefulness of the information for associative analyses.

National survey of risk factors for non-communicable disease in Vietnam: prevalence estimates and an assessment of their validity.

BACKGROUND: To estimate the prevalence of non-communicable disease (NCD) risk factors at a provincial level in Vietnam, and to assess whether the summary estimates allow reliable inferences to be drawn regarding regional differences in risk factors and associations between them. METHODS: Participants (n = 14706, 53.5 % females) aged 25-64 years were selected by multi-stage stratified cluster sampling from eight provinces each representing one of the eight geographical regions of Vietnam. Measurements were made using the World Health Organization STEPS protocols. Data were analysed using complex survey methods. RESULTS: Differences by sex in mean years of schooling (males 8.26 ± 0.20, females 7.00 ± 0.18), proportions of current smokers (males 57.70 %, females 1.73 %), and binge-drinkers (males 25.11 %, females 0.63 %), and regional differences in diet, reflected the geographical and socio-cultural characteristics of the country. Provinces with a higher proportion of urban population had greater mean levels of BMI (r = 0.82), and lesser proportions of active people (r = -0.89). The associations between the summary estimates were generally plausible (e.g. physical activity and BMI, r = -0.80) but overstated, and with some anomalous findings due to characterisation of smoking and hypertension by STEPS protocols. CONCLUSIONS: This report provides an extensive description of the sex-specific and regional distribution of NCD risk factors in Vietnam and an account of some health-related consequences of industrialisation in its early stages. The STEPS protocols can be utilized to provide aggregate data for valid between-population comparisons, but with important caveats identified.

Declining Prevalence of Tobacco Smoking in Vietnam.

INTRODUCTION: To supplement limited information on tobacco use in Vietnam, data from a nationally-representative population-based survey was used to estimate the prevalence of smoking among 25-64 year-olds. METHODS: This study included 14,706 participants (53.5% females, response proportion 64%) selected by multi-stage stratified cluster sampling. Information was collected using the World Health Organization STEPwise approach to surveillance of risk factors for non-communicable disease (STEPS) questionnaire. Smoking prevalence was estimated with stratification by age, calendar year, and birth year. RESULTS: Prevalence of ever-smoking was 74.9% (men) and 2.6% (women). Male ever-smokers commenced smoking at median age of 19.0 (interquartile range [IQR]: 17.0, 21.0) years and smoked median quantities of 10.0 (IQR: 7.0, 20.0) cigarettes/day. Female ever-smokers commenced smoking at median age of 20.0 (IQR: 18.0, 26.0) years and smoked median quantities of 6.0 (IQR: 4.0, 10.0) cigarettes/day. Prevalence has decreased in recent cohorts of men (p = .001), and its inverse association with years of education (p < .001) has strengthened for those born after 1969 (interaction p < .001). At 60 years of age, 53.0% of men who had reached that age were current smokers and they had accumulated median exposures of 39.0 (IQR: 32.0, 42.0) years of smoking and 21.0 (IQR: 11.5, 36.0) pack-years of cigarettes. The proportion of ever-smokers has decreased consistently among successive cohorts of women (p < .001). CONCLUSIONS: Smoking prevalence is declining in recent cohorts of men, and continues to decline in successive cohorts of women, possibly in response to anti-tobacco initiatives commencing in the 1990s. Low proportions of quitters mean that Vietnamese smokers accumulate high exposures despite moderate quantities of cigarettes smoked per day.

The importance of waist circumference and body mass index in cross-sectional relationships with risk of cardiovascular disease in Vietnam.

BACKGROUND: Waist circumference (WC) is an indicator of intra-abdominal adipose tissue, high levels of which confer an increased risk of cardiometabolic disease. Population data on WC should be more informative than data on body mass index (BMI), which is a general indicator of body size. This study aimed to evaluate the importance of WC relative to BMI in cross-sectional relationships with blood pressure (BP), glucose, and total cholesterol (TC) in the adult population of Vietnam. METHODS: The data were collected in a population-based survey conducted during 2009-10 using the "WHO STEPwise approach to surveillance of risk factors for non-communicable disease" (STEPS) methodology. The survey participants (n = 14 706 aged 25 to 64 years) were selected by multi-stage stratified cluster sampling from eight provinces representative of the eight geographical regions of Vietnam. All measurements were performed in accordance with the STEPS protocols. All analyses were performed using complex survey methods. RESULTS: The measurements of WC and BMI were highly correlated (men r = 0.80, women r = 0.77). For men, the strongest and predominant associations with BP, glucose, and TC were for WC or an index based on WC. For women, this was true for glucose but BMI was more important for BP and TC. WC or an index based on WC provided better discrimination than BMI of hypertension and elevated glucose, and of raised TC for men. Information on four new anthropometric indices did not improve model fit or subject discrimination. CONCLUSION: For BP/hypertension, glucose/elevated glucose, and TC/raised TC, WC was more informative than BMI for Vietnamese men, but both WC and BMI were important for Vietnamese women. Both WC and BMI need to be assessed for estimation of CVD risk in Vietnam.

Physical Activity in Vietnam: Estimates and Measurement Issues.

INTRODUCTION: Our aims were to provide the first national estimates of physical activity (PA) for Vietnam, and to investigate issues affecting their accuracy. METHODS: Measurements were made using the Global Physical Activity Questionnaire (GPAQ) on a nationally-representative sample of 14706 participants (46.5% males, response 64.1%) aged 25-64 years selected by multi-stage stratified cluster sampling. RESULTS: Approximately 20% of Vietnamese people had no measureable PA during a typical week, but 72.9% (men) and 69.1% (women) met WHO recommendations for PA by adults for their age. On average, 52.0 (men) and 28.0 (women) Metabolic Equivalent Task (MET)-hours/week (largely from work activities) were reported. Work and total PA were higher in rural areas and varied by season. Less than 2% of respondents provided incomplete information, but an additional one-in-six provided unrealistically high values of PA. Those responsible for reporting errors included persons from rural areas and all those with unstable work patterns. Box-Cox transformation (with an appropriate constant added) was the most successful method of reducing the influence of large values, but energy-scaled values were most strongly associated with pathophysiological outcomes. CONCLUSIONS: Around seven-in-ten Vietnamese people aged 25-64 years met WHO recommendations for total PA, which was mainly from work activities and higher in rural areas. Nearly all respondents were able to report their activity using the GPAQ, but with some exaggerated values and seasonal variation in reporting. Data transformation provided plausible summary values, but energy-scaling fared best in association analyses.