Objective: The aims of the study were to investigate the distribution of hip joint space width (JSW) in asymptomatic subjects without radiologic evidence of degeneration, and investigate the influence of age, sex, physical parameters, occupational activity, and smoking on JSW.
Materials and methods: The distribution of minimum JSW was determined in hip joints in standardized, weight-bearing pelvic radiographs of the Copenhagen City Heart Study: The Osteoarthritis Substudy cohort of 4151 subjects. Asymptomatic subjects without radiologic osteoarthritis were included (1018M/1554F). Occupational exposure to repeated daily lifting, smoking, and physical parameters were registered for each individual.
Results: Overall, female minimum JSW was significantly smaller compared with male JSW (P < 0.0001). Female minimum JSW decreased significantly with age (P < 0.0001), while male minimum JSW remained relatively unaltered throughout life (P(right) = 0319, P(left) = 0.18). Minimum JSW correlated positively with height, weight, and BMI, as did femoral head radius. Multiple logistic regression analysis revealed significant influence of sex and age on minimum JSW in females only. Positive or adverse effects of cigarette smoking on hip JSW were not documented. Type and duration of occupational exposure to repeated daily lifting did not affect hip JSW significantly.
Conclusion: Minimum JSW decreased progressively with age in women, while it was unaltered in men. A history of smoking or different occupational exposure to repeated daily lifting did not influence minimum hip JSW significantly. Differences in body mass index, height or weight did not significantly influence minimum hip joint JSW.