Table 2.

Risk factors for component failure

Characteristic	Proportion or mean in failures (n = 108)	Proportion or mean in nonfailures (n = 1332)	Risk ratio	Lower 95% CI	Upper 95% CI	p value
Mean age (years)	56 (11, 34–78)	58 (10, 19–91)	0.98 per each increased year	0.9602	0.9966	0.0213
Mean cup angle (degrees)	45 (7, 24–70)	44 (6, 25–66)	1.03 per each increased degree	1.0017	1.0673	0.0390
Sex						0.0315
Male	45 (42%)	742 (56%)	0.5996	0.3740	0.9557
Female	63 (58%)	590 (44%)	1.6678	1.0463	2.6741

In parentheses are SDs and ranges for mean values and percentages for counted values; CI = confidence interval.