The current study documents death due to external causes as a major public health challenge in China, reporting an overall mortality rate of 58.7 deaths per 100,000 Chinese residents annually. These estimates include 14.1 and 44.6 deaths (per 100,000) due to suicide and other external cause injuries, respectively. Notably, and in contrast to previous findings, we identified male gender as an important predictor of increased suicide mortality. Other risk factors for suicide included older age and residency in rural and North China. Transport accidents, accidental poisoning, and accidental falls were the leading causes of other external cause injuries in China. Male gender, older age, rural residence, and having no education were associated with increased mortality from other external cause injuries, while overweight appeared to decrease mortality from other external cause injuries. The present results emphasize the importance of death from external cause injury and highlight the need for a public health response focusing on its prevention in the Chinese population.
Suicide is a major cause of premature death and thus is an important public health issue worldwide, particularly in China. In this study, we estimated suicide mortality to be 14.1 per 100,000, which is lower than previous reports potentially due to the exclusion of younger individuals in our study. Phillips' study reported an average suicide mortality rate of 23 per 100,000 yearly during the period of 1995-1999 in China. Yip and colleagues document a decrease in suicide mortality from 22.9 in 1991 to 15.4 per 100,000 in 2000. Qin and colleagues projected national suicide rates of 17.7-22.6 per 100,000 during the period of 1987-1994. All of the previous studies used vital statistical data provided by the Chinese Ministry of Health[2, 5, 15]. Due to the lack of a national death registration system, the validity of these data could not be confirmed. To the best of our knowledge, the current study is the first large prospective study conducted in China to estimate suicide mortality in a nationally representative adult population.
Our study showed that suicide was 2.8 times more common in rural areas than in urban areas. Similar findings have been shown in other studies in China and in other populations across the world[2, 5, 7, 8, 15, 18]. Some factors associated with living in a rural environment that may contribute to an increased suicide rate include lower socioeconomic status, traditional belief system, and less developed social networks[5, 19]. Easier access to highly poisonous agents such as pesticides and more difficult access to health services in rural China could lead to a higher proportion of completed suicide attempts[2, 6].
Notably, we found a slight increase risk of suicide for men after adjusted for multiple co-variables. In our study, suicide mortality is higher for men in middle-age groups (<60 years) and higher for women in the older age groups (≥60 years). By urbanization, suicide mortality for rural men exceeds that of rural women, whereas this relationship is reversed in urban areas. The majority of the literature identifies China as being one of few countries with a higher suicide rate for women than men, which seems to be primarily attributable to an excess of suicide fatalities among younger women residing in rural areas[2, 5–7, 9]. Younger persons (<40 years), however, were excluded from our study. The findings of Parker and colleagues also show an increase in the male to female ratio for suicide in Singapore during the 1990s, with a relatively greater decrease for females, and especially among the Chinese.
The elderly are particularly susceptible to suicide[6, 21]. In the present study, suicide rates dramatically increased with age. Suicide risk among the elderly could be a consequence of increased terminal illness, disability, and depression[6, 22, 23]. With regard to other suicide risk factors that have been suggested in prior studies [7, 13, 24, 25], although we found significant associations between BMI, employment and education with suicide, these were not significant after adjustment. In addition, we document residence in north China as a risk factor and found that smoking and drinking habits were not related to suicide.
Transport injuries rank among the leading causes of death worldwide. Among transport injuries, motor vehicle accidents are responsible for the majority of deaths, particularly in younger age groups. In our study, transport accidents accounted for the majority (28.8%) of overall external cause fatalities. Accidental drowning, falls, and poisoning are also major causes of injury death, which is consistent with the World Health Organization Global Burden of Disease estimates. It is possible that some suicides committed by ingesting poison such as pesticides were misclassified as accidental poisoning deaths, thereby overestimating the number of deaths due to accidental poisoning and underestimating the number of deaths due to suicide. However, mortality from all external causes should be accurate because both suicide deaths and other external cause injuries were examined in the current study.
The overall mortality due to other external cause injuries was 44.6 per 100 000 in the study population. Men had a higher rate of mortality due to other external cause injuries compared to women. Elderly persons are particularly vulnerable to death resulting from injury due to increased susceptibility to complications and given that there is poor access to medical care in rural China. In addition to age and sex, other socio-demographic factors and health behaviors, such as urbanization and being uneducated, are related to injuries after accounting for covariates. Being overweight was associated with lower risk of death due to other external cause injuries in this study population.
The principal strength of our study is its prospective cohort design and large, national representative sample. Due to the lack of a complete death registry, accurate estimates of mortality from external cause injuries in China were not previously available. Given the sampling methods employed, these results can be generalized to the overall Chinese population and possibly to other countries with similar characteristics. Furthermore, accuracy of cause of death was ensured by death certificates and/or hospital records in our study. We examined the association of socio-demographic risk factors that were not investigated in previous studies, such as BMI category, employment status, education level, smoking and drinking on mortality from external cause injuries in China.
Due to the national representativeness of this study, the identification of demographic factors and other characteristics can be used to develop national programs for the prevention of external cause injury mortality. For the prevention of injuries and violence, the World Health Organization advises enforcement of seat-belt use and helmets, restricting access to means of committing suicide such as pesticides, limiting access to bodies of water, improving health services for victims of injury and violence and developing crisis centers[27, 28]. In a systematic review of suicide prevention programs worldwide, physician education and reducing access to lethal means to commit suicide were found to prevent suicide. Continued research to assess patterns in rates of suicide and other external cause injuries and to evaluate prevention programs is warranted.