Self-reported drug use and mortality among a nationwide sample of Swedish conscripts - a 35-year follow-up

Drug users in clinical samples have elevated mortality compared with the general population, but little is known about mortality among users of drugs within the general population.

To determine whether self-reported use of illicit drugs and non-prescribed sedatives/hypnotics among young men in the general population is related to mortality.

A 35-year follow-up of 48024 Swedish men, born 1949-1951 and conscripted in 1969/1970, among whom drug use was reported by 8767 subjects. Cross-record linkage was effected between individual data from the Swedish conscription and other national registers. Deaths and causes of death/1000 person-years were calculated. Cox PH regression was used to estimate hazard ratios (HRs) for death with 95% confidence intervals (95% CIs). An HR was calculated for users of different dominant drugs at conscription compared with non-users by age interval, after adjusting for confounders and hospitalisation with a drug-related diagnosis.

Drug users showed elevated mortality (HR 1.61, p<0.05) compared with non-users. After adjusting for risk factors, users of stimulants (HR 4.41, p<0.05), cannabis (HR 4.27, p<0.05), opioids (HR 2.83, p>0.05), hallucinogens (HR 3.88, p<0.05) and unspecified drugs (HR 4.62, p<0.05) at conscription with a drug-related diagnosis during follow-up showed an HR approaching the standard mortality ratios in clinical samples. Among other drug users (95.5%), only stimulant users showed statistically significantly increased mortality (HR 1.96, p<0.05).

In a life-time perspective, drug use among young men in the general population was a marker of premature death, even a long time after exposure.