Jiaying Zhao

Timing of urbanisation and cardiovascular risks in Thailand: evidence from 51 936 members of the Thai Cohort Study, 2005-2009

Background Urban populations usually have higher levels of cardiovascular risk factors than rural populations in developing countries. However, association between cardiovascular risk factors and duration of urban dwelling, particularly for early stages of urban migrations, has not yet been adequately studied. We examined cardiovascular risks in relation to timing of urbanization in Thailand, paying attention to recent internal migrants. Methods Our study base was a large national cohort (n = 87 151) of distance-learning Thai open university students recruited in 2005 and followed up in 2009. After exclusion of longitudinal dropouts and reverse migrants, 51 936 remained for analyses. The information collected included historical residence, urban migration and its lifecycle timing, self-reported doctor-diagnosed diseases, and socio-demographic and personal attributes that could influence health. To relate cardiovascular outcomes (prevalence and incidence of hypertension and hyperlipidaemia) and life-course urbanization status (ie at age 12, 4 years ago [2005] and at present [2009]), we applied logistic regression. Included in the models were 10 other covariates that could confound the urbanization effect. Results Recent migration (arriving within four years) among young cohort members (born after 1980) was associated with higher risk of hypertension (OR 1.80 for prevalence and 1.68 for four-year incidence). Higher hyperlipidaemia prevalence (and incidence) was associated with any urban dwelling. Recent migrants quickly developed hyperlipidaemia, particularly the youngest (born after 1980) and oldest participants (born before 1960). Conclusions Increased cardiovascular risks appear among rural-urban migrants within four years after they arrive. Given the scale of continuing urbanization, interventions are needed to support and educate recent migrants in Thai cities.

Relationship between Body Mass Index Reference and All-Cause Mortality: Evidence from a Large Cohort of Thai Adults

We investigate variation in body mass index (BMI) reference and 5-year all-cause mortality using data from 87151 adult Open University students nationwide. Analyses focused on BMI reference bands: “normal” (≥18.5 to <23), “lower normal” (≥18.5 to <20.75), “upper normal” (≥20.75 to <23), and “narrow Western normal” (≥23 to <25). We report hazard ratios (HR) and 95% Confidence Intervals adjusting for covariates. Compared to lower normal, adults aged 35–65 years who were obese (BMI ≥ 30) were twice as likely to die during the follow-up (HR 2.37; 1.01–5.70). For the same group, when using narrow Western normal as the reference, the results were similar (HR 3.02; 1.26–7.22). However, different combinations of BMI exposure and reference band produce quite different results. Older age persons belonging to Asian overweight BMI category (≥23 to <25) were relatively protected from mortality (HR 0.57; 0.34–0.96 and HR 0.49; 0.28–0.84) when assessed using normal (≥18.5 to <23) and upper normal (≥20.75 to <23) as reference bands. Use of different “normal” reference produced varying mortality relationships in a large cohort of Thai adults. Caution is needed when interpreting BMI-mortality data.

Self-reported health and subsequent mortality: an analysis of 767 deaths from a large Thai cohort study

BackgroundFew studies have examined the link between self-reported health (SRH) and subsequent mortality in developing countries, and very few considered mortality effects of changes in SRH. We examined the relationship between SRH and subsequent all cause or cause-specific mortality in Thailand. We also noted if mortality varied after people changed their SRH.MethodsWe used longitudinal data including SRH from a nationwide Thai Cohort Study (baseline 2005 - follow-up 2009) and linked to official death records (2005–2012). Cox regression examined the association between SRH in 2005 and subsequent all-cause mortality or cause-specific mortality, with results given as confounder-adjusted hazard ratios (HR). We further assessed association between changes in SRH during 2005–2009 and mortality from 2009 to 2012.ResultsPoor SRH at baseline independently relates strongly with subsequent cardiovascular disease (CVD) mortality (HR = 2.8, CI: 1.3-5.9) and “other” causes of death (HR = 1.9, CI: 1.1-3.3) but moderately with cancer mortality (HR = 1.4, CI: 0.7-3.0). SRH did not exhibit a relationship with injury mortality (HR = 1.0, CI: 0.5-2.1). Worsening SRH from 2005 to 2009 associated with increased mortality in 2009–2012 for females but not for males.ConclusionsIn Thailand, SRH is a good predictor of population mortality due to internal causes (e.g. CVD). SRH is holistic, simple to measure and low cost; when repeated it measures dynamic health status. In many developing countries chronic diseases are emerging and morbidity information is limited. SRH could help monitor such transitions in burdens and trends of population health.

Mortality in China: Data sources, trends and patterns

While China has continued to make impressive progress in lowering its mortality, there are few detailed studies on how has this happened, on the major characteristics of Chinese mortality in comparison to many other countries, or on the major lessons learned from China’s mortality decline. This is partly because mortality studies in China have long been overshadowed by those on fertility, and is also partly attributable to lack of knowledge and limited accessibility of some mortality data.

Long-term mortality changes in East Asia: Levels, age patterns, and causes of death

One of the most significant events in recent history has been the worldwide demographic transition. This transition started with mortality decline in some European countries around the beginning of the nineteenth century. While mortality reduction started late in most East Asian populations, their life expectancies have increased faster than those observed in Europe. In recent years, Japan and Hong Kong have achieved the highest life expectancy and led the mortality decline in the world. These changes raise many important research questions and have significant implications. This chapter examines long-term mortality changes in East Asia and compares them with those observed in England and Wales, France and Sweden. Its discussion particularly concentrates on changes in age-specific mortality rates and their contribution to the increase of life expectancies in recent history. To explain these changes and their patterns, the chapter also analyses changes in major causes of death and their impacts on mortality decline across different age groups. On the basis of its major research findings, the chapter concludes with a brief discussion of several factors and their contribution to the rapid mortality transition in East Asia in recent decades.

Ultra-low fertility, gender equity and policy considerations

Purpose The purpose of this paper is to focus on the issue and the reasons why fertility patterns in many industrialized and post-industrialized societies decline so rapidly, primarily in newly industrialized countries, particularly in East Asia, and especially after the countries have adopted the capitalist and market economy as the preferred approach to improve the lives of their population. Design/methodology/approach The authors discuss gender equality and the relationship between fertility and female labor force participation in industrialized and post-industrialized countries, in the context of role incompatibility, mainly for women and the level of the strength and rigidity of family- and gender-role norms/attitudes that affect the behaviors of men and women. Findings The existing family-related policies and programs which have reduced the role conflict and incompatibility experienced by working mothers are reviewed and discussed under national orientations toward the resolution of work–family conflict since they could affect the relevance, acceptance, significance and effectiveness of policies being developed and approved to carry on under institutional context within a nation. Originality/value Specific strategies and policies to reduce role incompatibility and childcare arrangements and their costs are discussed, especially for East Asian nations.

Cardiovascular mortality sex differentials in selected East Asian and Western populations

Background Explaining patterns in the sex ratio (male/female) of cardiovascular disease (CVD) mortality would improve understanding of mortality transitions under modernisation. Little research has examined secular trends in this ratio across populations, taking age and cohort into account. We examine cohort effects in the ratios of CVD mortality (including ischaemic heart disease and cerebrovascular disease) among 4 East Asian populations that vary in the timing of their modernisation, and assess the effect of smoking on these patterns in comparison with Western populations. Methods The sequential method for log-linear models is applied to analyse age, period and cohort effects for sex ratios. Age and cohort effects are fitted first, with population as offset; period effects are fitted in a second model using the fitted values from the first model as the offset. Lung cancer mortality serves as a proxy for smoking. Results Increases in sex ratios of CVD mortality began in earlier cohorts in Western than in East Asian populations. Once begun, increases were more rapid in East Asia. The cohort effect for the sex ratio of CVD mortality differs from that for lung cancer mortality. Trends in sex ratios of CVD mortality by cohort are similar before and after adjustment for lung cancer mortality in East Asia; the increasing trend across 1900–1945 cohorts is maintained in Western populations after adjustment. Conclusions The sex ratio of CVD mortality has increased across successive cohorts living in increasingly modernised environments. There is scant evidence that this increase is attributable to changing sex-specific rates of smoking.

Risk Factors for Cardiovascular Disease Mortality Among 86866 Members of the Thai Cohort Study, 2005-2010

Thailand is experiencing a development-associated health-risk transition with increasing prominence of chronic diseases. We aim to determine the risk factors for cardiovascular disease (CVD) deaths in Thailand. We conducted longitudinal analyses of deaths in the nationwide Thai Cohort Study from 2005 to 2010 (n=86866) using national vital registration data. Multivariate logistic regression models were used to calculate mutually adjusted estimates of association between dying from CVD and various risk factors measured at baseline in 2005. For three important risks, population attributable fractions were calculated. There were 78 CVD deaths. The probability of dying from CVD for males was 0.15% and for females was 0.04%. Multivariate modelling showed that current smoking (OR=4.01, CI=2.02-7.93), hypertension (OR=1.91, CI=0.95-3.85), and diabetes (OR=2.51, CI=1.01-6.25) are major risk factors of CVD deaths. For males, 54% of CVD deaths can be attributed to smoking. Females are protected by very low rates of smoking. Ischaemic heart disease (OR=6.85, CI=2.47-19.01) is also a strong predictor of CVD deaths. As CVD is a top cause of death, reducing CVD mortality by controlling smoking, hypertension, and hyperglycaemia will substantially improve life expectancy in Thailand today. The low smoking rates among females need to be actively maintained and confer great benefit.

The Effects of Economic Transition on Mortality in Shanghai, China

Much research has linked an increase in adult mortality with the socioeconomic transition of former European socialist societies after 1989. Few studies examine corresponding experiences in China, however. Using the death certificates of Shanghai residents, we examined any such sudden mortality change and crisis when China went through economic transformation. We explored trends in life expectancy at birth and age-specific mortality in Shanghai. We applied Arriaga’s decomposition method to analyze the contributions of specific ages and the causes to the changes in life expectancy. We used harmonic regression models to assess the statistical significance of rising and falling mortality over time. The analysis shows that, coinciding with the economic transition of 1992–1996, the previously steady improvement of life expectancy in Shanghai slowed down. Mortality among working-age males (20–44 years old) increased (P