The findings presented in Chapter 2 of this thesis show that mean levels of BMI and blood cholesterol, and proportions of persons with hypertension and diabetes, were consistent with values reported for Southeast Asian nations, but lower than those for Western nations (1, 6). The summary information presented on socio-demographic, behavioural and
pathophysiological factors reflects the changing NCD risk factor profile of a country undergoing industrialization/urbanisation. For example, the findings that greater schooling and income were associated with reduced PA but higher BMI are consistent with previous reports (7-10). Urbanisation was associated with a higher prevalence of overweight/obesity, hypertension and diabetes, and these findings are consistent with those for other populations (11, 12). Increased adiposity and hypertension are a predicted consequence (8, 13) of the urbanisation that Vietnam has experienced in the recent past (14). Although re-constructed birth cohort analyses of body size/fatness were not possible with the cross-sectional data collected on body size, mean waist circumference not explained by age and mean WHR not explained by age have increased in recent birth cohorts of both men and women (analyses not reported). These findings strengthen the case for interventions to promote healthy eating and PA in order to prevent future increases in overweight/obesity and its probable consequences of hypertension, elevated glucose and hypercholesterolemia even though the mean levels or
Chapter 7. Summary, implications and future research 150 150 prevalence of these risk factors are not at alarming levels at present. Our findings in respect of the sex, urban-rural and regional differences in the mean levels or prevalence of
pathophysiological risk factors provide valuable information that could help public health authorities in planning and evaluating NCD intervention strategies. For instance, the sex- difference in proportions with raised blood pressure highlights the need for sex-specific interventions to address risk factors. Reducing prevalence of tobacco smoking by men, an established risk factor for hypertension, should be a priority. Besides the implementation of interventions exclusively targeting specific behavioural risk factors, there is a need to implement multiple-faceted interventions because previous findings have shown that behavioural risk factors often cluster among individuals, and success in changing one risk behaviour might increase motivation and self-confidence, or serve as a “gate way”, to change other risky behaviours (15-17).
The findings presented in Chapter 3 of this thesis suggest that the decline in smoking prevalence in more recent birth cohorts of adult men coincided with the introduction of tobacco control initiatives commencing in the 1990s. Our findings are consistent with the evidence (18) that key tobacco control interventions (19) including excise tax increases, mass media campaigns, and public and work place smoking bans are cost-effective in Vietnam. However, the prevalence of tobacco smoking among men remains high, and a low quit rate is likely to predispose most of those who start smoking to premature mortality and morbidity. The cost-effective interventions cited, together with other approaches such as point-of-sale restrictions and graphic warning labels on cigarette packs (18), should be maintained and implemented more widely. In addition to those interventions, the importance of strengthening strategies to encourage current smokers in Vietnam to quit smoking, and to assist them to do so by offering cessation advice integrated in primary health-care activities, counselling services, and low-cost pharmacological therapy, needs to be emphasized (20).
Our findings on smoking prevalence among women suggest that product promotion strategies used by tobacco companies (examples include mass media, sponsorships, point-of-sale advertising and product placement in films when allowed) have not succeeded to date with Vietnamese women. The findings are consistent with evidence that smoking by women is considered by Vietnamese people to be inappropriate and associated with “loose morals” (21). Social mores on smoking may play an important role in dissuading women from initiating smoking, and this appears to be the case in Vietnam. But it may not last. In Western countries
prior to the 1950s, smoking by women was widely disparaged as lacking refinement but that attitude was gradually worn down by a series of product changes implemented from the 1950s onwards – the introduction of manufactured cigarettes, the addiction of cork tips (to preserve a woman’s lipstick) and then filter-tips – together with aggressive marketing of menthol cigarettes to women as providing freshened breath and oral hygiene (22, 23). Increased prevalence of smoking by Vietnamese women is predicted by the smoking diffusion model based on Western experience (24-28), and anticipated as a consequence of increased
marketing efforts by tobacco companies in developing countries (29). If so, whilst there is no need for it at present, public health interventions designed to prevent smoking uptake by Vietnamese women may need to be strengthened in the future.
Although alcohol use and harmful consumption is less pronounced in Vietnam than in Western countries (30), these behaviours are much more common among Vietnamese men than women. This may reflect the cultural practice in Vietnam and in other Asian countries (31). Because there are strong links between hazardous/harmful and binge drinking and chronic disease outcomes such as hypertension (32, 33), CVD (2, 34) and stroke (3),
culturally appropriate public health strategies to reduce hazardous/harmful drinking behaviour are needed, particularly for men. Increasing alcohol beverage excise taxes, restricting access to retailed alcohol beverages, and comprehensive advertising, promotion and sponsorship bans have been shown to be cost-effective in Vietnam (35), and they need to be maintained with the objective of reducing or limiting growth in prevalence of this risky behaviour.
The results presented in Chapter 5 of this thesis confirm that the proportion of Vietnamese people not meeting WHO physical activity recommendations is generally lower than those reported in Western countries (1). Nevertheless, our data show that work activity comprises a major portion of total PA and, unless PA in other domains (transport and leisure) can be increased by cost-effective interventions, overall PA will decline if work activity diminishes in response to further industrialization/urbanisation. Reduced work and total PA has already occurred in China (36) where, similar to Vietnam, work and total PA are significantly lower in more urbanised provinces and in the urban areas of rural provinces. Whilst birth cohort analyses of PA could not be conducted with these cross-sectional data, mean total PA not
explained by age has declined in the most recent birth cohorts (the 197579 and 198084
birth cohorts) of both men and women (analyses not reported). At present, more than three quarters of Vietnamese people do not undertake any measurable leisure-time activity, and
Chapter 7. Summary, implications and future research 152 152 spend no time on walking or biking to get to and from places. Mass media campaigns to motivate and support individuals and communities to be more active will need to be
implemented if increased leisure and transport activity are to compensate for future declines in work activity. Encouraging people to walk or cycle to and from places, and to spend more time in leisure activity, by mass media campaigns is among the most cost-effective of interventions to promote PA (37).
The proportion of Vietnamese people meeting the WHO recommendation for fruit and vegetable intake is generally similar to, or even higher than, the findings in other developing (38) and Western (39, 40) countries. Whilst more than 90% of Vietnamese people consume at least one serving of fruit or vegetables per day, only one-in-five consume at least five servings of fruit and vegetables as recommended by WHO. A recent meta-analysis of data from 16 prospective cohort studies mostly conducted in Western countries have shown that higher consumption of fruit and vegetables is associated with a reduced risk of all-cause mortality,
with an average reduction in risk of 56% for each additional serving of fruit or vegetables
(41). Even if further industrialization is accompanied by increased consumption of fruit and vegetables, which is a plausible implication of the positive associations found in this thesis between fruit and vegetable intake and education or income, those benefits could be enhanced by effective interventions to further increase consumption. The results of a survey conducted in Austria show that the greatest barrier to increasing the number of servings is the perception that the current consumption of an individual was already sufficient (42). The findings
suggest that strategies to increase intake of fruit and vegetables should pay more attention to those barriers, and to recognition that each additional serving consumed has beneficial effects on health. A further strategy worth considering is that being used in developed countries such as Australia to increase fruit and vegetable consumption in rural areas not serviced by
supermarkets and specialist green grocers. That strategy is to encourage community gardens to develop and to support them to grow.