Table 4.

Among ever smokers, hazard ratios for total mortality according to cumulative smoking pack-years after RA diagnosis/index date in the Nurses’ Health Study.

Pack-years after RA or index date	Deaths/Person-years	Mortality rate*	Age-adjusted HR (95% CI)	Age and pre-RA/index smoking adjusted HR (95% CI)1	Age, pre-RA/index smoking, and BMI adjusted HR (95% CI)2	Multivariable HR (95% CI)3
RA cohort (n=597)
0	122/6,267	1,947	1.00 (Ref)	1.00 (Ref)	1.00 (Ref)	1.00 (Ref)
>0 to 5	47/2,095	2,243	1.59 (1.12–2.25)	1.45 (1.01–2.08)	1.38 (0.96–2.00)	1.33 (0.91–1.95)
>5	67/1,692	3,724	2.97 (2.12–4.15)	2.60 (1.81–3.74)	2.63 (1.81–3.80)	2.43 (1.64–3.58)
Comparison cohort (n=4,914)
0	688/53,678	1,282	1.00 (Ref)	1.00 (Ref)	1.00 (Ref)	1.00 (Ref)
>0 to 5	215/16,548	1,299	1.44 (1.23–1.68)	1.21 (1.03–1.42)	1.25 (1.06–1.47)	1.33 (1.13–1.57)
>5	361/16,514	2,186	2.09 (1.84–2.38)	1.62 (1.40–1.86)	1.69 (1.46–1.95)	1.93 (1.66–2.24)

Each RA case was matched with up to 10 women without RA on age and calendar year at index date to form the comparison cohort.

^*Per 100,000 person-years.

¹Adjusted for age, questionnaire period, and cumulative smoking prior to RA diagnosis/index date (never, >0–10, >10–20, >20 pack-years).

²Adjusted for age, questionnaire period, cumulative smoking prior to RA diagnosis/index date (never, >0–10, >10–20, >20 pack-years), and BMI category (underweight, normal, overweight, obese).

³Adjusted for age, questionnaire period, cumulative smoking prior to RA diagnosis/index date (never, >0–10, >10–20, >20 pack-years), BMI category (underweight, normal, overweight, obese), physical activity (hours of moderate or vigorous exercise per week, continuous), census-tract household family income (<$40K, $40K+ per year), Alternative Healthy Eating Index score (tertiles), and Multimorbidity Weighted Index (continuous).

BMI, body mass index; CI, confidence interval; HR, hazard ratio; RA, rheumatoid arthritis; SD, standard deviation.