Table 3

Multiple regression analysis of the factors associated with the incidence of Perthes' disease in the period 1990–95  

B t p value
Change in z score for deprivation between 1976 and 19952.6703.196 0.003
Percent low birth weight in 19813.3612.7060.011
Percent free school meals in 1986−0.233−2.356−0.026
Health index in 1981 (z score)−2.425−2.0160.054
  • R2 44%; df (4, 28); F ratio = 5.53; p value = 0.002.

  • Data for ward deprivation rates were only available for Liverpool City. The table is based on 33 wards, not 78. B is the regression coefficient. The table indicates that the incidence of LCPD changes 2.67 units per unit change in z score. R2 represents the percentage variation explained by the variables in the model.