Emerging tobacco hazards in China: 1. Retrospective proportional mortality study of one million deaths

Abstract

Objective: To assess the hazards at an early phase of the growing epidemic of deaths from tobacco in China.

Design: Smoking habits before 1980 (obtained from family or other informants) of 0.7 million adults who had died of neoplastic, respiratory, or vascular causes were compared with those of a reference group of 0.2 million who had died of other causes.

Setting: 24 urban and 74 rural areas of China.

Subjects: One million people who had died during 1986-8 and whose families could be interviewed.

Main outcome measures: Tobacco attributable mortality in middle or old age from neoplastic, respiratory, or vascular disease.

Results: Among male smokers aged 35-69 there was a 51% (SE 2) excess of neoplastic deaths, a 31% (2) excess of respiratory deaths, and a 15% (2) excess of vascular deaths. All three excesses were significant (P<0.0001). Among male smokers aged >/70 there was a 39% (3) excess of neoplastic deaths, a 54% (2) excess of respiratory deaths, and a 6% (2) excess of vascular deaths. Fewer women smoked, but those who did had tobacco attributable risks of lung cancer and respiratory disease about the same as men. For both sexes, the lung cancer rates at ages 35-69 were about three times as great in smokers as in non-smokers, but because the rates among non-smokers in different parts of China varied widely the absolute excesses of lung cancer in smokers also varied. Of all deaths attributed to tobacco, 45% were due to chronic obstructive pulmonary disease and 15% to lung cancer; oesophageal cancer, stomach cancer, liver cancer, tuberculosis, stroke, and ischaemic heart disease each caused 5-8%. Tobacco caused about 0.6 million Chinese deaths in 1990 (0.5 million men). This will rise to 0.8 million in 2000 (0.4 million at ages 35-69) or to more if the tobacco attributed fractions increase.

Conclusions: At current age specific death rates in smokers and non-smokers one in four smokers would be killed by tobacco, but as the epidemic grows this proportion will roughly double. If current smoking uptake rates persist in China (where about two thirds of men but few women become smokers) tobacco will kill about 100 million of the 0.3 billion males now aged 0-29, with half these deaths in middle age and half in old age.

Figure 1

Location of study areas: 24 major cities (large circles with names) and 74 rural counties (open unnamed circles). The study areas for Fuzhou city include two small unmarked nearby cities, and those for Beijing exclude one district (out of eight in that city) where the study organisation failed. Provincial boundaries are shown

Figure 2

Smoking prevalence in 1990 among interviewees whose spouse had died in 1986-8

Figure 3

Numbers of deaths of smokers and non-smokers aged 35-69 from lung cancer and all causes other than neoplastic, respiratory, or vascular disease (reference group) together with relative risks and 99% confidence intervals. Results presented for men and women by study region. Height of each square is inversely proportional to length of confidence interval

Figure 4

Death rates at ages 35-69 from lung cancer in smokers versus non-smokers, 1986-8. For women (right) the rates for six of the smaller cities have been averaged (dark square)

Figure 5

Death rates of male smokers and non-smokers aged 35-69 in 1986-8 from four main categories of cause

Figure 6

Death rates of female smokers and non-smokers aged 35-69 in 1986-8 from four main categories of cause