The Interdependence of Blood Pressure and Glucose in Vietnam.

INTRODUCTION: Modelling of associations of systolic blood pressure (BP) and blood glucose (BG) with their explanatory factors in separate regressions treats them as having independent biological mechanisms. This can lead to statistical inferences that are unreliable because the substantial overlap in their etiologic and disease mechanisms is ignored. AIM: This study aimed to examine the relationship of systolic blood pressure (BP) and blood glucose (BG) with measures of obesity and central fat distribution and other factors whilst taking account of the inter-dependence 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. RESULTS: Structural modelling identified direct effects for BG (men P = 0.000, women P = 0.029), age (men P = 0.000, women P = 0.000) and body mass index (BMI) (men P = 0.000, women P = 0.000) in the estimation of systolic BP, and for systolic BP (men P = 0.036, women P = 0.000) and waist circumference (WC) (men P = 0.032, women P = 0.009) in the estimation of BG. There were indirect effects of age, cholesterol, physical activity and tobacco smoking via their influence on WC and BMI. The errors in estimation of systolic BP and BG were correlated (men P = 0.000, women P = 0.004), the stability indices (men 0.466, women 0.495) showed the non-recursive models were stable, and the proportion of variance explained was mid-range (men 0.553, women 0.579). CONCLUSION: This study provided statistical evidence of a feedback loop between systolic BP and BG. BMI and WC were confirmed to be their primary explanatory factors. Saturated fat intake and physical activity were identified as possible targets of intervention for overweight and obesity, and indirectly for reducing systolic BP and BG. Harmful/hazardous alcohol intake was identified as a target of intervention for systolic BP.

Physical activity and its association with cardiovascular risk factors in Vietnam.

This study examined physical activity in leisure time and at work as estimated by the Global Physical Activity Questionnaire (GPAQ) and the associations between both total and domain-specific physical activity with cardiovascular risk factors in a population-based Vietnamese sample. Participants (n = 1978) were 25- to 64-year-old adults selected by stratified multistage sampling. Leisure activity contributed to <5% of total moderate and vigorous activity and was not associated with cardiovascular risk factors. Total moderate and vigorous activity was associated with body composition (r = -0.16 to -0.22; P < .001), blood glucose (r = -0.07; P < .05), and total cholesterol (r = -0.17; P < .001) for men and with total cholesterol (r = -0.07; P < .05) for women after adjusting for age. Further adjustment for smoking and alcohol intake made negligible changes. These associations were largely driven by work activity, which accounted for 80% of total activity.

Using pedometers to estimate ambulatory physical activity in Vietnam.

BACKGROUND: Pedometer measurement of physical activity (PA) has been shown to be reliable and valid in industrialized populations, but its applicability in economically developing Vietnam remains untested. This study assessed the feasibility, stability and validity of pedometer estimates of PA in Vietnam. METHODS: 250 adults from a population-based survey were randomly selected to wear Yamax pedometers and record activities for 7 consecutive days. Stability and concurrent validity were assessed using intraclass correlation coefficients (ICC) and Spearman correlation coefficients. RESULTS: Overall, 97.6% of participants provided at least 1 day of usable recordings, and 76.2% wore pedometers for all 7 days. Only 5.2% of the sample participants were involved in work activities not measurable by pedometer. The number of steps increased with hours of wear. There was no significant difference between weekday and weekend in number of steps, and at least 3 days of recordings were required (ICC of the 3 days of recordings: men 0.96, women 0.97). Steps per hour were moderately correlated (men r = .42, women r = .26) with record estimates of total PA. CONCLUSIONS: It is feasible to use pedometers to estimate PA in Vietnam. The measure should involve at least 3 days of recording irrespective of day of the week.

The association between smoking and hypertension in a population-based sample of Vietnamese men.

OBJECTIVE: The association between tobacco smoking and blood pressure in epidemiological studies remains unclear despite experimental evidence that smoking elevates blood pressure. This study examined the association between smoking and hypertension in a population-based sample of Vietnamese men. METHODS: The study utilized a population-based sample of men (n = 910) from a survey of risk factors of noncommunicable diseases in Vietnam. Measurements including behavioural risk factors, body composition, and blood pressure were performed according to internationally standardized protocols. Poisson regression was used to obtain prevalence ratios and 95% confidence intervals (CIs). All analyses were performed using complex survey methods. RESULTS: There were significant trends of increasing prevalence of hypertension with increasing years (P = 0.05) and pack-years (P = 0.03) of smoking after adjusting for age, BMI, and alcohol intake. Relative to never-smokers, the risk of hypertension for those who had smoked for 30 years or more and those who had smoked 20 pack-years or more were 1.52 (95% CI 0.95-2.44) and 1.34 (95% CI 0.94-1.91), respectively. Overall, however, current smokers were not at higher risk of hypertension than never-smokers (prevalence ratio = 1.08, 95% CI 0.70-1.68), and ex-smokers were more likely to be hypertensive than either never-smokers (prevalence ratio = 1.81, 95% CI 1.07-3.06) or current smokers (prevalence ratio = 1.67, 95% CI 1.25-2.23), similarly adjusted. CONCLUSION: In this population-based sample, hypertension was associated with smoking in a dose-response manner when characterized as number of years of smoking and lifetime cigarette consumption, but was not associated with current smoking status.