Trends in hip fracture rates in Canada: An age-period-cohort analysis

Abstract

Age-standardized rates of hip fracture in Canada declined during the period 1985 to 2005. We investigated whether this incidence pattern is explained by period effects, cohort effects, or both. All hospitalizations during the study period with primary diagnosis of hip fracture were identified. Age-and sex-specific hip fracture rates were calculated for nineteen 5-year age groups and four 5-year calendar periods, resulting in 20 birth cohorts. The effect of age, calendar period, and birth cohort on hip fracture rates was assessed using ageperiod-cohort models as proposed by Clayton and Schiffers. From 1985 to 2005, a total of 570,872 hospitalizations for hip fracture were identified. Age-standardized rates for hip fracture have progressively declined for females and males. The annual linear decrease in rates per 5-year period were 12% for females and 7% for males (both p < 0.0001). Significant birth cohort effects were also observed for both sexes (p < 0.0001). Cohorts born before 1950 had a higher risk of hip fracture, whereas those born after 1954 had a lower risk. After adjusting for age and constant annual linear change (drift term common to both period and cohort effects), we observed a significant nonlinear birth cohort effect for males (p ¼ 0.0126) but not for females (p ¼ 0.9960). In contrast, the nonlinear period effect, after adjustment for age and drift term, was significant for females (p ¼ 0.0373) but not for males (p ¼ 0.2515). For males, we observed no additional nonlinear period effect after adjusting for age and birth cohort, whereas for females, we observed no additional nonlinear birth cohort effect after adjusting for age and period. Although hip fracture rates decreased in both sexes, different factors may explain these changes. In addition to the constant annual linear decrease, nonlinear birth cohort effects were identified for males, and calendar period effects were identified for females as possible explanations. ß

Age–period–cohort effects in the incidence of hip fractures: political and economic events are coincident with changes in risk

“…Nevertheless, New Zealand [7] and Sweden [8] have reported a continuous decrease in risk for younger cohorts but contrasting period effects with New Zealand showing a continuous increase versus a continuous decrease in Sweden. A recent study in Canada [10] also identified a decreased risk in younger cohorts and a non-linear effect of cohort in men. However, unlike our study, no fluctuations in risk were identified for birth cohorts.…”

“…Few studies have reported the use of combined analysis to untangle the age-period-cohort (APC) effects [7][8][9][10]. The age effect in hip fracture incidence has been well described showing that the risk of fracture increases exponentially in the elderly [11].…”

Tendencia secular de la incidencia de la fractura de cadera en el mundo

“…Jean et al 13 analyzed whether the pattern observed by Leslie's group could be explained by a period effect, a birth cohort effect, or both. They appreciated significant period effects both in men and women.…”

Cumulative incidence and treatment of non-simultaneous bilateral femoral neck fractures in a cohort of one thousand two hundred and fifty patients

“…Despite a declining trend in hip fractures in western countries (7)(8)(9)(10)(11), a worldwide increase is expected as a result of aging of populations by improving health care globally and increasing industrialization and urbanization (12). An increase in incidence of the first hip fracture implies that an increase in incidence of a subsequent hip fractures is to be expected as well.…”