Mortality among Substance-using Mothers in California: A 10-year prospective study

Aims: To examine mortality rates and causes of death among a cohort of substance-using mothers and to identify risk factors that predict mortality. Design, setting, participants: This is a prospective study of a cohort of 4,447 substance-using mothers (pregnant or parenting) who were enrolled during 2000 to 2002 in 40 drug abuse treatment programs across California. Methods: All mothers were assessed at baseline using the Addiction Severity Index. Mortality data were obtained from the National Death Index and causes of death were coded using ICD-10. Standardized mortality ratios (SMR) were calculated relative to women in the general population adjusted for age. Proportional hazard (Cox) regression was used to identify risk factors predicting death. Findings: By the end of 2010, 194 deaths were confirmed, which corresponds to a crude mortality rate of 4.47 per 1000 person-years, and SMR of 8.4 (95% CI=7.2-9.6). Drug overdose (28.8%), cardiovascular disease (10%), and alcohol or drug disorders (8.9%) were the leading causes of death. Factors associated with higher mortality included older age, being white (relative to African American or Hispanic), using heroin, alcohol, cocaine, or marijuana (relative to methamphetamine use), drug injection, and higher severity in employment, medical/health, and psychiatric problems. Conclusions: Substance-using mothers face problems in many key life areas which may contribute to their elevated risk for mortality. Substance use was a critical factor related to death among this sample, thus addressing such problems in the lives of women may prevent pre-mature deaths.