Table 3.

Risk of Incident Cancer and Periodontal Disease^a according to Hormone Therapy Use (E-Alone or E+P)^b The Women’s Health Initiative Observational Study

	Total Nc	Total Cancer Cases	Hazard Ratio HR (95% CI)d	P-valuee
Never	17,665	2,092	1.06 (0.96 – 1.17)	0.23
Former	13,762	1,495	1.08 (0.96 – 1.21)	0.19
Current	30,928	3,746	1.18 (1.10 – 1.27)	<0.01

^aAnalyses of individual cancer sites were based on time to diagnosis of primary cancer for that particular site, independent of findings from other cancer sites; however, for the evaluation of regional- and total cancers, we considered the time to first diagnosis of any cancer located within that group, whichever came first. Therefore, the sum of the individual cancers may not exactly approximate the values obtained when those cancers are considered as a group.

^bP-value level of significance for interaction term set a priori at 0.2; p-value obtained for interaction of PD with Hormone Therapy use was 0.17.

^cNumber of valid responses with annualized risk, percentages (in parenthesis).

^dHR (95% CI): Hazard ratio and 95% Confidence Interval. Hazard ratios (HR) and annualized risk percentage NOT computed for cancer sites with <20 cases.

^eP-value for Cox proportional hazards according to various strata; statistical significance level set at p<0.05.