Table 7.

Modification of the effect of diabetes mellitus on risk of developing cataracts by hypertension

	Diabetes Mellitus (DM)				RR (95% CI); p for with versus without DM within strata of hypertension
	No		Yes
Hypertension	%	RR (95% CI)	%	RR (95% CI)
No	2852/7502 (38%)	1.0	345/531 (65%)	1.7 (1.4–2.2) p < 0.01	1.7 (1.4–2.2) p < 0.01
Yes	1757/2735 (64%)	1.2 (1.1–1.3) p < 0.01	565/736 (77%)	2.0 (1.6–2.5) p < 0.01	1.1 (0.9–1.5) p = 0.37

Measure of effect modification on additive scale: RERI (95% CI) = 0.1(−0.5 ~ 0.6); p = 0.85.

Measure of effect modification on multiplicative scale: ratio of RRs (95% CI) = 1.0 (0.7 ~ 1.3); p = 0.78.

RRs are adjusted for age, sex, household monthly income, and education.

RR: relative risk, RERI; relative excess risk due to interaction, CI; confidence interval.