To investigate nutritional status and related living conditions among drug addicts in Oslo.

A cross-sectional study of nutritional status evaluated by anthropometric and biochemical measurements; a structured interview concerning education, living conditions, income source, drug history and sex practice; and biochemical testing of sexually transmitted infections.

The present study was conducted between November 2001 and April 2003 in locations where the drug addicts reside in Oslo.

A total of 123 male and seventy-two female addicts using drugs by injections regularly.

We found that 20 % of the women were moderately underweight (BMI in kg/m2) (16·5 < BMI < 18·5), 7 % were severely underweight (BMI ≤ 16·5) and 3 % of the men were moderately underweight (16·5 < BMI < 18·5). BMI was positively correlated with days institutionalised and number of eating events per day. Respondents sleeping rough had significantly reduced BMI compared to those in hostels and shelters. The concentrations of Hb, serum ferritin and albumin supported a higher prevalence of malnutrition among the women. Hepatitis C was found in 85 %, active hepatitis B in 6 % and less than 2 % were HIV positive. Also, 84 % received public financial support, 38 % of the women had prostitution as a significant income source, while burglary was most prevalent among the men; 20 % were pushing drugs.

Malnutrition among the drug addicts varied from 5 % to 30 %, independent of drug history, education and income. Moderate and severe underweight was most prevalent among the women. Being previously institutionalised and having increased number of eating events increased BMI. Sleeping rough correlated with reduced body weight. Hepatitis C infection was common; hepatitis B and HIV were rare.