Sickness absence diagnoses among abstainers, low-risk drinkers and at-risk drinkers: consideration of the U-shaped association between alcohol use and sickness absence in four cohort studies

Aims: To estimate differences in the strength and shape of associations between alcohol use and diagnosis-specific sickness absence.

Design: A multi-cohort study. Participants (n = 47 520) responded to a survey on alcohol use at two time-points, and were linked to records of sickness absence. Diagnosis-specific sickness absence was followed for 4-7 years from the latter survey.

Setting and participants: From Finland, we had population cohort survey data from 1998 and 2003 and employee cohort survey data from 2000-02 and 2004. From France and the United Kingdom, we had employee cohort survey data from 1993 and 1997, and 1985-88 and 1991-94, respectively.

Measurements: We used standard questionnaires to assess alcohol intake categorized into 0, 1-11 and > 11 units per week in women and 0, 1-34 and > 34 units per week in men. We identified groups with stable and changing alcohol use over time. We linked participants to records from sickness absence registers. Diagnoses of sickness absence were coded according to the International Classification of Diseases. Estimates were adjusted for sex, age, socio-economic status, smoking and body mass index.

Findings: Women who reported drinking 1-11 units and men who reported drinking 1-34 units of alcohol per week in both surveys were the reference group. Compared with them, women and men who reported no alcohol use in either survey had a higher risk of sickness absence due to mental disorders [rate ratio = 1.51, 95% confidence interval (CI) = 1.22-1.88], musculoskeletal disorders (1.22, 95% CI = 1.06-1.41), diseases of the digestive system (1.35, 95% CI = 1.02-1.77) and diseases of the respiratory system (1.49, 95% CI = 1.29-1.72). Women who reported alcohol consumption of > 11 weekly units and men who reported alcohol consumption of > 34 units per week in both surveys were at increased risk of absence due to injury or poisoning (1.44, 95% CI = 1.13-1.83).

Conclusions: In Finland, France and the United Kingdom, people who report not drinking any alcohol on two occasions several years apart appear to have a higher prevalence of sickness absence from work with chronic somatic and mental illness diagnoses than those drinking below a risk threshold of 11 units per week for women and 34 units per week for men. Persistent at-risk drinking in Finland, France and the United Kingdom appears to be related to increased absence due to injury or poisoning.