LIFE-STYLE FACTORS AND HIP ARTHROSIS - A CASE-REFERENT STUDY OF BODY-MASS INDEX, SMOKING AND HORMONE-THERAPY IN 503 SWEDISH WOMEN

We investigated in a case-referent study the relationship between arth rosis of the hip in women and lifestyle factors such as body mass inde x (BMI), smoking and hormone therapy. The study comprised all women of ages 50-70 years, living in 5 counties and 5 towns in Sweden 1991-199 4. The cases (n 230) were women with total hip replacements (THR) beca use of primary arthrosis, and the referents (n 273) were randomly sele cted women from the study base, without hip problems. All women were i nterviewed about height, weight, smoking habits, hormone therapy, spor ts activities, occupational history, home work, etc, to the age of 50. The relative risk of developing hip arthrosis leading to a THR after the age of 50 was associated with an increased BMI, The highest value, 2.9 (CI 1.3-6.5), was reported in those with BMI greater than or equa l to 25 at the age of 40. The preventive value of weight loss seems su bstantial. There was a greater risk of 1.5 (CI 1.0-2.2) for smokers th an for non-smokers, Use of contraceptive pills meant an increase in th e relative risk for THR, unlike estrogen substitution which was associ ated with a lower risk than in unexposed persons.