Yanping Wu

Patterns of Lung Function in Asymptomatic Nonsmoking Men and Women in the People's Republic of China

PURPOSE To evaluate patterns of lung function in healthy, working Chinese men and women in different geographic areas of the Peoples Republic of China (PRC). METHODS We conducted lung function tests on 2926 asymptomatic, never smoking Chinese men and women aged 35-56 years residing in or around Beijing and Guangzhou. Within each of these locations, separate urban and rural samples were recruited. RESULTS Age and height adjusted lung function was greater in Beijing than in Guangzhou, and within each city for residents of rural vs. urban areas. Among women, estimated rates of lung aging were greater in Beijing than in Guangzhou, and in urban vs. rural areas. Both FEV(1) and FVC exhibited a curvilinear association with body mass index. CONCLUSIONS Lung function data from this largely working cohort exhibited marked geographic and urban-rural differences in this never smoking, adult Chinese cohort. Such variation is not uncommon and may reflect differences in body size, diet, and environmental and occupational exposures across these different settings. Caution should be used in applying published reference equations to populations from different parts of the PRC.

Age-related Effects of Smoking on Lung Cancer Mortality: A Nationwide Case-Control Comparison in 103 Population Centers in China

PURPOSE To examine age-related effects of smoking on lung cancer mortality in a large population-based case-control study that was incorporated into a nationwide retrospective survey of mortality in China. METHODS Two data sets were pooled for this analysis: national mortality survey data and data from a nationwide case-control comparison. These pooled data were used to calculate age-specific lung cancer death rates by smoking status and expected years of lost life expectancy for each smoking-associated death. RESULTS There was a significant excess of deaths (54% of urban deaths, 51% of rural deaths) at 35 to 69 years of age among male smokers and the average loss of life expectancy per smoking-associated death at these ages was 18.3 years. For women ages 35 to 69 years of age, 29% and 11% excess lung cancer mortality was observed in urban and rural smokers, respectively, with an average loss of life expectancy per smoking-associated death of 21.3 years. CONCLUSIONS Tobacco smoking was associated with a large number of deaths from lung cancer. Utilizing information from a population-based retrospective mortality survey for conducting an analytic epidemiological study of main determinants of disease is feasible and can generate important results.

Smoking-attributable deaths and potential years of life lost from a large, representative study in China

Objectives To provide a more accurate estimate of early smoking-attributable mortality and potential years of life lost using data from a representative study of 103 study areas in China. Methods Two datasets were employed as follows. Firstly, retrospective national mortality survey data, which included a population of 67 million in 103 study areas, and about 1 million adults who died in 1986–1988; secondly, nationally representative case-control comparative data was extracted from the survey data to measure the effect of smoking on age trends in smoking-attributable mortality. Potential years of life lost, and sex differences in life expectancy in smokers and non-smokers in the total population aged 35 and over were also estimated. Results Tobacco caused 11.2% (16.0% of men and 3.7% of women) of total deaths in 1987, and more than two-thirds of these excess deaths occurred between the ages of 50 and 74 years, but only less than 5% excess deaths occurred at ages under 50. Although life expectancies varied with region or sex differences, the years of life lost attributable to smoking was almost the same. Smokers at age 35 lost about 3 years of life expectancy in comparison with never smokers. The study also confirmed that more than 50% of the sex difference in life expectancy was accounted for by smoking. Conclusion Fully understanding the consequences of smoking in relation to mortality can clarify its effects on the health and longevity of the entire population.

Passive smoking and stroke in men and women: a national population-based case-control study in China

An association between passive smoking and stroke is unclear in China, particularly the association with hemorrhagic stroke. This study included 16205 deaths due to stroke aged ≥30 years and 16205 non-stroke controls randomly selected and frequency-matched to cases on gender and age. Smoking of spouses, defined as ≥1 cigarette per day for up to 1 year, was taken as a measure of exposure to passive smoking of subjects that was retrospectively ascertained by interviewing surviving spouses. After adjustment for variables, passive smoking increased the risk of death by 10% (odds ratio (OR), 1.10; 95% confidence interval (CI), 1.05–1.16) for all strokes, by 10% (OR, 1.10; 95% CI, 1.04–1.16) for hemorrhagic stroke, and by 12% (OR, 1.12; 95% CI, 1.03–1.23) for ischemic stroke, compared with non-exposure. This finding was highly consistent in men or women and in smokers or non-smokers, and was generally consistent among zones of China despite geographic diversity. The risk significantly increased with exposure-years and quantity of cigarettes smoked daily by spouses. This study indicated that passive smoking is associated with deaths from all-type strokes. It is highly advisable for the government to promote strong tobacco prevention and cessation programs and smoke-free environments.

Smoking and adult glioma: a population-based case-control study in China

BACKGROUND Smoking increases the risk of numerous cancers; however, an association of smoking with adult gliomas has not been found in a population. METHODS This case-control study included 4556 glioma cases (ICD-9 code 191.0-191.9) aged ≥ 30 years and 9112 controls from a national survey of smoking and mortality in China in 1989-1991. Controls from 325 255 surviving spouses of all-cause deaths were randomly assigned to cases in each of 103 areas according to sex and age groups at a ratio of 2:1. Smoking information was ascertained retrospectively by interviewing surviving spouses. RESULTS After adjustment for confounders, smoking increased the risk of glioma deaths by 11% (odds ratio [OR] = 1.11; 95% confidence interval [CI]: 1.03-1.21). Compared with non-smokers; the increased risk was 9% (OR = 1.09; 95% CI: 0.99-1.20) in men and 16% (OR = 1.16; 95% CI: 1.00-1.36) in women. The risk increased with age and doses. For individuals aged ≥ 50 years, smoking was associated with higher risk of glioma death by 25% (OR = 1.25; 95% CI: 1.15-1.38); this increased risk for smokers who smoked ≥ 20 cigarettes daily for ≥ 30 years was 53% (OR = 1.53; 95% CI: 1.34-1.74). There were similar findings in both men and women and with either pathology-based or non-pathology-based comparisons. CONCLUSIONS This study indicates that smoking is associated with glioma deaths in the Chinese population. Long-term heavy smoking could be a factor for risk stratification in individuals attending brain tumor clinics.

Case-spouse control design in practice: an experience in estimating smoking and chronic obstructive pulmonary disease deaths in Chinese adults.

BACKGROUND/PURPOSE We assessed the effect of smoking on death from chronic obstructive pulmonary disease (COPD) in China by employing a large population-based, case-spouse control study design using data from a nationwide survey of mortality. METHODS During 1989-1991, a nationwide retrospective survey of mortality was conducted in China. For approximately 1,000,000 adults dying from all causes during 1986-1988, their surviving spouses or other informants provided detailed information about their own as well as the deceased persons smoking history. For this study, 183,393 individuals who died of COPD at age > or = 40 years were taken as cases, while 272,984 sex-matched surviving spouses of subjects who died from any cause were taken as controls. RESULTS COPD death rates for smokers were more than twice as high as those of non-smokers, with a dose-response risk pattern, despite the fact that COPD death rates varied widely by region and age. Tobacco accounted for 41.4% of COPD deaths in men, but only 13.5% of those in women, who had a lower rate of smoking. CONCLUSION A case-spouse control study, as an alternative design, is valid and feasible in utilizing information from population-based, retrospective mortality survey data for an analytical epidemiological study of disease etiology.