Family history and risk of hospital treatment for varicose veins in Sweden

Abstract

Abstract Background Family history has been suggested as a risk factor for varicose veins, but recall bias may inflate the familial risks. The aim of this nationwide study was to determine familial risks for hospital treatment for varicose veins. Methods Data from the Swedish Multi-Generation Register of people aged 0-76 years were linked to Hospital Discharge Register data for 1964–2008. Standardized incidence ratios (SIRs) were calculated for individuals whose relatives were treated in hospital for varicose veins and compared with those whose relatives were not. Only main diagnoses of varicose veins were considered. Results A total of 39 396 people had hospital treatment for varicose veins. The familial SIR among offspring with one affected parent was 2·39 (95 per cent confidence interval 2·32 to 2·46). The SIR for those with one affected sibling was 2·86 (2·76 to 2·97). SIRs were increased in both men and women. The SIR for individuals with two or more affected siblings or with two affected parents was 5·88 (5·28 to 6·53) and 5·52 (4·77 to 6·36) respectively. The SIR for the wives of men treated for varicose veins was 1·69 (1·59 to 1·80); that for the husbands of women treated for varicose veins was 1·68 (1·58 to 1·79). Conclusion Using the Swedish Hospital Discharge Register, and thereby eliminating recall bias, family history of hospital treatment for varicose veins was associated with an increased risk of similar treatment among relatives. The increased spousal risk suggests a contribution from non-genetic factors.