Jilei Wu

Twenty-year trends in the prevalence of disability in China

OBJECTIVE To evaluate changes in the age-adjusted prevalence of disability in transitional China from 1987 to 2006. METHODS Data from nationally representative surveys conducted in 1987 and 2006 were used to calculate age-adjusted disability prevalence rates by applying appropriate sample weights and directly adjusting to the age distribution of the 1990 Chinese population. Trends were assessed in terms of average annual percentage change. FINDINGS The estimated number of disabled people in China in 1987 and 2006 was 52.7 and 84.6 million, respectively, corresponding to a weighted prevalence of 4.9% and 6.5%. The age-adjusted prevalence of disability decreased by an average of 0.5% per year (average annual percentage change, AAPC: -0.5%; 95% confidence interval, CI: -0.7 to -0.4) during 1987-2006. However, it increased by an average of 0.3% (AAPC: 0.3%; 95% CI: 0.1 to 0.5) per year in males and by an average of 1.0% (AAPC: 1.0%; 95% CI: 0.8 to 1.2) per year among rural residents, whereas among females it showed an average annual decrease of 1.5% (AAPC: -1.5%; 95% CI: -1.7 to -1.3) and among urban residents, an average annual decrease of 3.9% (AAPC: -3.9%; 95% CI: -4.3 to -3.5). Despite significant declining trends for hearing and speech, intellectual and visual disabilities, the annual age-adjusted prevalence of physical and mental disabilities increased by an average of 11.2% (AAPC: 11.2%; 95% CI: 10.5 to 11.9) and 13.3% (AAPC: 13.3%; 95% CI: 10.7 to 16.2), respectively. CONCLUSION In China, the age-adjusted prevalence of disability has declined since 1987, with inconsistencies dependent on the type of disability. These findings call for continuing and specific efforts to prevent disabilities in China.

Spatial dynamics of an epidemic of severe acute respiratory syndrome in an urban area

OBJECTIVE To map risk of exposure to severe acute respiratory syndrome (SARS) in an urban area and assess the ability of traditional interventions to control dispersion of the disease. METHODS Data on the Beijing SARS epidemic were used to map spatial clusters of identified contacts and to estimate transmission of SARS using a model with a time-dependent transmission rate. RESULTS The estimated transmission rate decreased dramatically from 20 to 30 April 2003. The total number of cases in the epidemic in Beijing was estimated to be 2521. Hierarchical clustering revealed that risk-exposures were widespread, but clustered in a pattern that is distinctly related to the Beijing urban ring roads. CONCLUSION Traditional control measures can be very effective at reducing transmission of SARS. Spatial patterns of risk-exposures can inform disease surveillance, prediction and control by identifying spatial target areas on which interventions should be focused.

Spatial analysis of neural tube defects in a rural coal mining area

Shanxi province in northern China has one of the highest reported prevalence rates of neural tube defects (NTDs) in the world. The current study selected Heshun, the county with the highest rate of NTDs in Shanxi, as a study area and tested whether residence in a coal mining area was a contributing factor. A NTD cluster was detected in an area within 6 km of the coal mines for almost every year during 1998–2005. Poisson regression analysis revealed that there may be an association between production in coal mines and prevalence of NTDs in coal mine areas. Future work identifying factors independently correlated with NTDs in coal mining regions may provide further insights into the health effects of coal mines on NTDs.

Household air pollution and personal exposure to nitrated and oxygenated polycyclic aromatics (PAHs) in rural households: Influence of household cooking energies.

Residential solid fuels are widely consumed in rural China, contributing to severe household air pollution for many products of incomplete combustion, such as polycyclic aromatic hydrocarbons (PAHs) and their polar derivatives. In this study, concentrations of nitrated and oxygenated PAH derivatives (nPAHs and oPAHs) for household and personal air were measured and analyzed for influencing factors like smoking and cooking energy type. Concentrations of nPAHs and oPAHs in kitchens were higher than those in living rooms and in outdoor air. Exposure levels measured by personal samplers were lower than levels in indoor air, but higher than outdoor air levels. With increasing molecular weight, individual compounds tended to be more commonly partitioned to particulate matter (PM); moreover, higher molecular weight nPAHs and oPAHs were preferentially found in finer particles, suggesting a potential for increased health risks. Smoking behavior raised the concentrations of nPAHs and oPAHs in personal air significantly. People who cooked food also had higher personal exposures. Cooking and smoking have a significant interaction effect on personal exposure. Concentrations in kitchens and personal exposure to nPAHs and oPAHs for households using wood and peat were significantly higher than for those using electricity and liquid petroleum gas (LPG).

Unusual Patterns of Neural Tube Defects in a High Risk Region of Northern China

OBJECTIVE To study the prevalence of different types of neural tube defects (NTDs) in Luliang Prefecture, Shanxi province, where the prevalence of NTDs is unusually high and the correlation between NTDs prevalence and patterns. METHODS A surveillance population-based birth defects was performed in Luliang Prefecture, Shanxi province. RESULTS The results of our study showed that the prevalence of NTDs was 2-fold higher in Luliang Prefecture than in other areas of Shanxi province. Unusual patterns of NTDs were found, however, multiple NTDs were relatively common in Luliang Prefecture, accounting for over 13% of all NTDs cases in China. CONCLUSION The prevalence of NTDs is associated with its patterns.

Regional variations in and correlates of disability- free life expectancy among older adults in China

BackgroundConsiderable socioeconomic and health inequalities have been reported in China. However, because of a lack of appropriate data, limited research has been conducted on variations in disability-free life expectancy (DFLE) among older adults. This study aimed to use the most up-to-date disability survey data to explore geographical variations in DFLE at age 60 in China and to identify the socioeconomic and health care factors that partially account for these variations.MethodsThis study used 2006 mortality data extrapolated from the 1990 and 2000 Census and disability data from a national disability survey conducted in 2006. Disability was performance based and was diagnosed by trained physicians. DFLE was calculated by region using the Sullivan method. Multiple linear regression models by gender were conducted to explore correlates of DFLE.ResultsDFLE at age 60 varied widely by region, from 11.2 to 20.8 years in 2006. Per capita gross domestic product, proportion of urban residents, and access to health care were the primary factors associated with geographical variations in DFLE.ConclusionThe pattern of differences in DFLE by region mirrors the pattern of regional economic development in China. Countermeasures to decrease regional differences in DFLE include accelerating regional economic development and improving health care distribution.

Association between risk of birth defects occurring level and arsenic concentrations in soils of Lvliang, Shanxi province of China.

The risk of birth defects is generally accredited with genetic factors, environmental causes, but the contribution of environmental factors to birth defects is still inconclusive. With the hypothesis of associations of geochemical features distribution and birth defects risk, we collected birth records and measured the chemical components in soil samples from a high prevalence area of birth defects in Shanxi province, China. The relative risk levels among villages were estimated with conditional spatial autoregressive model and the relationships between the risk levels of the villages and the 15 types of chemical elements concentration in the cropland and woodland soils were explored. The results revealed that the arsenic levels in cropland soil showed a significant association with birth defects occurring risk in this area, which is consistent with existing evidences of arsenic as a teratogen and warrants further investigation on arsenic exposure routine to birth defect occurring risk.

Interaction between the SLC19A1 gene and maternal first trimester fever on offspring neural tube defects

BACKGROUND Many studies have indicated that the reduced folate carrier gene (SLC19A1) is associated with an increased risk of neural tube defects (NTDs). However, the interaction between the SLC19A1 gene variant and maternal fever exposure and NTD risk remains unknown. The aim of this study was to investigate whether the risk for NTDs was influenced by the interactions between the SLC19A1 (rs1051266) variant and maternal first trimester fever. METHODS We investigated the potential interaction between maternal first trimester fever and maternal or offspring SLC19A1 polymorphism through a population-based case-control study. One hundred and four nuclear families with NTDs and 100 control families with nonmal newborns were included in the study. SLC19A1 polymorphism was determined using polymerase chain reaction-restricted fragment length polymorphism. RESULTS Mothers who had the GG/GA genotype and first trimester fever had an elevated risk of NTDs (adjusted odds ratio, 11.73; 95% confidence interval, 3.02-45.58) as compared to absence of maternal first trimester fever and AA genotype after adjusting for maternal education, paternal education, and age, and had a significant interactive coefficient (γ = 3.17) between maternal GG/GA genotype and first trimester fever. However, there was no interaction between offsprings GG/GA genotype and maternal first trimester fever (the interactive coefficient γ = 0.97) after adjusting for confounding factors. CONCLUSION Our findings suggested that the risk of NTDs was potentially influenced by a gene-environment interaction between maternal SLC19A1 rs1051266 GG/GA genotype and first trimester fever. Maternal GG/GA genotype may strengthen the effect of maternal fever exposure on NTD risk in this Chinese population.

Periconceptional Multivitamin Supplementation Containing Folic Acid and Sex Ratio at Birth in a Chinese Population: a Prospective Cohort Study.

BACKGROUND To determine whether periconceptional use of multivitamin supplements containing folic acid increases the occurrence of male births in a Chinese population. METHODS A prospective cohort study was carried out in 18 counties in four provinces of China. Participants were naturally and voluntarily divided into an intervention group (who took a multivitamin pill containing folic acid, n = 25,418) and a control group (who did not take any multivitamin, n = 26,580). Multivitamin supplements containing folic acid was ascertained before pregnancy. Pregnant women were followed through the first trimester of pregnancy and the outcome of pregnancy (i.e. livebirth, stillbirth, or fetal death; sex at birth) was recorded. RESULTS A total of 52,043 pregnancies and 51,998 births were recorded between September 2000 and August 2002. The proportion of males born to women who did and did not take the multivitamin were 54.8% (n = 13,935) and 54.0% (n = 11,483), respectively. The male to female sex ratios at birth among women who did and did not take the multivitamin were 117:100 and 121:100, respectively. The risk ratio was 1.03 [95% confidence interval 0.99, 1.06] after adjusting for confounding factors. CONCLUSIONS These findings suggest that periconceptional multivitamin supplementation containing folic acid is not associated with an increased likelihood of male births in a Chinese population. However, these results may have been affected by induced abortion or selective termination of pregnancy, and the findings must therefore be cautiously interpreted.

Tendencias de la prevalencia de discapacidad en China a lo largo de veinte años

Introduction Disability is common in both developed and developing countries. (1) An estimated 650 million people worldwide live with some form of disability. (2) The way that disability is conceived has changed substantially in recent years, the current focus being on three areas of impairment: bodily functions and structures, activities and participation. (2) In this study, disability is defined as one or more abnormalities in anatomical structure or the loss of a particular organ or function (either physical or psychological) affecting a persons ability to carry out a normal activity and to participate fully in study, work, and community and social life. In the United States of America, about 50 million adults suffer from various forms of disability, including hearing loss, visual impairment, cognitive impairment and limited mobility. (3) In China, about 85 million people have a disability or another condition that affects their daily lives and social activities. (4) Furthermore, disability can lead to limited access to education, health care and rehabilitation services, to the detriment of the disabled people, their families and local communities, health-care systems and social security systems. (1,5) Therefore, specific strategies, policy initiatives and sustainable programmes are needed to improve the health status of the disabled population. Several studies have explored trends in disability among different populations. According to prevalence estimates, in the United States 51.2 million people aged 6 years or older (18.1% of the age group) reported having a disability in 2002, compared with 54.4 million (18.7%) in 2005. (6) Freedman et al. (7) systematically reviewed cross-sectional and cohort studies and reported a general decrease in the age-adjusted prevalence of disability in the population aged 65 years of age or older in the United States. A similar decrease in disability prevalence was reported for Spains population aged 65 years or older. (8) In terms of life expectancy, the Netherlands reported an increase in the number of years lived with minor disabilities (9) and Japan reported a decrease in the number of years lived with severe disabilities. (10) These mixed findings may be attributable to different indicators, disability contexts and study populations. (11) In China, two large-scale nationally representative household surveys were conducted from 1 April to 30 May in 1987 and 2006. (12,13) The resulting figures have been used in epidemiological studies to conduct specific analyses of different types of disabilities, (14-21) rural/urban disparities in disability prevalence (4) and disability-free life expectancy. (22) Using different survey series, Phillips et al. (23) described the prevalence of mental disorders in four provinces, and Chou and Leung (24) evaluated self-reported disability among the elderly in Hong Kong Special Administrative Region. These studies have primarily provided a demographic profile of people with disability in China. However, there is no scientific evidence of the magnitude of the problem of disability across the entire nation that will allow for complex survey designs and age-adjusted analysis of trends in disability prevalence nationwide. China has undergone rapid social, economic, political, institutional and demographic transitions. Thus, understanding the magnitude of the burden of disability and its trends over time is essential for improving the health of the population and enhancing the lives of people with disabilities. In this study, our primary objective was to assess changes in the prevalence of disability in China during the 20-year period from 1987 through 2006. We also aimed to investigate any changes in the leading causes of disability that may have occurred over that time and that could potentially explain the changes in overall prevalence. Since 80% of all those who are disabled live in developing countries, (25) most of which are going through an epidemiologic and sociodemographic transition, the findings from this study may be broadly reflective of disability trends in the developing world at large. …