To explore the trends and distribution of suicide between genders, ages and urban-rural areas from 1999 to 2015 in Tianjin, and provide basis for prevention and control of suicide.

Suicide mortality data in 1999-2015 were obtained from Tianjin population based mortality surveillance system operated by the Tianjin Centers for Disease Control and Prevention (CDC), and population data of permanent residents were from Tianjin Municipal Public Security Bureau. Standardized mortality rates were calculated for suicide, adjusted for age and gender by using the year 2000 world standard population. Joinpoint regression and Cochran-Armitage trend were used to determine the statistical significance of differences in mortality trends.

Suicide mortality in Tianjin was observed from year 1999 to 2015 with the crude mortality rate of 4.76/100 000 to 4.07/100 000. Adjusted suicide mortality rate from 1999 to 2006 was 4.28/100 000 to 2.59/100 000, indicating an decreased trend (Z=-9.37, P<0.01) with an annual percent change (APC) of -7.80%. Adjusted suicide mortality rate was increased from 2006 to 2015: 2.59/100 000 to 3.00/100 000 (Z=2.15, P=0.032), and APC was 1.54%. Adjusted suicide mortality rate of male was declined from 1999 to 2007: 4.77/100 000 to 2.86/100 000 (Z=-7.43, P<0.01, APC= -6.89%) , and increased from 2007 to 2015: 2.86/100 000 to 3.49/100 000 (Z=3.13, P=0.002, APC=3.44%). Adjusted suicide mortality rate of female was declined from 1999 to 2006: 3.79/100 000 to 2.04/100 000 (Z=-6.85, P<0.01, APC= -7.82%) , and flatted from 2006 to 2015: 2.04/100 000 to 2.50/100 000 (Z=-0.16, P=0.871). The suicide standardized mortality rate of male was generally higher than that of female during the 17 years. The suicide mortality rate increased with age. Adjusted suicide mortality rate in urban was declined from 1999 to 2007: 3.09/100 000 to 1.94/100 000 (Z=-5.45, P<0.01, APC= -6.15%) , and flatted from 2007 to 2015: 1.94/100 000 to 2.44/100 000 (Z=1.43, P=0.154). Adjusted suicide mortality rate in rural was declined from 1999 to 2005: 5.65/100 000 to 3.03/100 000 (Z=-7.55, P<0.01, APC=-9.70%) , and increased from 2005 to 2015: 3.03/100 000 to 3.73/100 000 (Z=2.69, P=0.007, APC=1.71%). Except in the year of 2005, the suicide mortality rate was significantly higher in rural residents than in urban residents during this study period (P<0.05). The proportions of method of suicide including hanging, poisoning with pesticides, dumping from a height, drowning, poisoning with drugs and sharp instrument injury were 32.09%, 28.30%, 12.88%, 8.87%, 6.81% and 2.93% respectively. Hanging was the predominant method of suicide among male or in urban area. Poisoning with pesticides was a major problem, notably among female or in rural area. Drowning and poisoning with drugs was much common among female than male (P<0.01). Dumping from a height and drowning was much common in urban than rural (P<0.01).

The suicide mortality in Tianjin decreased dramatically from 1999 to 2006, and increased slightly from 2006 to 2015, and male and rural residents have higher suicide mortality. The methods of suicide were different between male and female, and between urban and rural areas. Further efforts of lifestyles improvement, primary prevention, restricting access to the means of suicide and first-aid treatment for suicide are needed to reduce suicide and mortality in Tianjin.

Suicide; Mortality; Population surveillance; Epidemiology