Table 3. Risk of Kidney Failure by Smoking Status in Singapore Chinese Cohort Study.

Smoking status	Number Kidney Failure	*Adjusted HR (95% CI)
Never smoker (n = 43859)	443	1.00
Former smoker (n = 6976)	108	1.42 (1.07–1.87)
Current smoker (n = 12327)	122	1.28 (0.98–1.65)
P trend		0.04
Never smoker (n = 43859)	443	1.00
Ever smoked < = 12 cigarettes/day (n = 7693)	95	1.27 (1.00–1.61)
Ever smoked 13–22 cigarettes/day (7331)	76	1.15 (0.88–1.50)
Ever smoked > = 23 cigarettes/day (n = 4280)	60	1.37 (1.01–1.84)
P trend		0.03

^*Model adjusted for age, body mass index, dialect (Hokkein, Cantonese), education level, history of physician diagnosed hypertension, diabetes, known heart disease or stroke, alcohol use and intake of ginseng.