Table 2. Crude and adjusted hazard ratios for the association between the use of contaminated ranitidine with incident cancer in the propensity score-matched cohort (n = 55,584)

NDMA exposure	N (%)	Cancer events	Person-years	Cancer incidence rate*	HR (95% CI)
					Adjusted§	Fully adjusted‡
No exposure	27,792	2,840	173,511	16.4	1.00 (reference)	1.00 (reference)
Exposure	27,792	2,913	171,722	17.0	1.01 (0.95 to 1.06)	1.01 (0.95 to 1.06)
Cumulative exposure (mg)
<70,000	9,901	1,010	60,786	16.6	1.05 (0.97 to 1.12)	1.05 (0.98 to 1.13)
70,000-129,999	9,098	937	56,329	16.6	0.99(0.92 to 1.07)	0.99 (0.92 to 1.07)
≥130,000	8,793	966	54,606	17.7	0.98 (0.91 to 1.05)	0.98 (0.91 to 1.05)
P for trend					0.483	0.429
Cumulative duration of use (yr)
<1	14,391	1,455	88,786	16.4	1.03 (0.96 to 1.09)	1.03 (0.97 to 1.10)
1-2	7,670	826	47,339	17.4	1.00 (0.93 to 1.09)	1.00 (0.93 to 1.08)
≥2	5,731	632	35,597	17.8	0.96 (0.88 to 1.05)	0.96 (0.88 to 1.05)
P for trend					0.611	0.549

Abbreviations here: CI, confidence interval; H2 blocker, histamine H2 receptor antagonist; HR, hazard ratio; NDMA, N-nitrosodimethylamine; SD, standard deviation.
Cancer incidence rate is expressed as per 1,000 person-years.
Risk factors were adjusted for age and sex.
Risk factors were adjusted for age; sex; frequency of alcohol consumption; region of residence (rural or urban); body mass index (<25, 25–30, or ≥30 kg/m²); systolic blood pressure, diastolic blood pressure, fasting blood glucose, and serum total cholesterol (continuous variables); history of diabetes mellitus, stroke, or hypertension; Charlson comorbidity index (0-1, 2, or ≥3), alcoholic drinks (<1, 1-2, 3-4, or ≥5 days per week); household income (low, middle, or high), smoking (never smoker, ex-smoker, or current smoker); physical activity (0, 1–2, 3–4, 5–6, or 7 sessions per week); and use of a proton pump inhibitor, statin, systemic glucocorticoid, metformin, aspirin, or hormone replacement therapy.
Number in bold indicate significant differences (P < 0.05).