Table 2.

Weight change from young adulthood to midlife and risk of developing an arthritis conditions, NHANES 1988–1994 & 1999–2016 (n=13,669)

Weight Changea	Number of Incident Arthritis Conditionsb	Incidence (95% CI)c	HR (95% CI)d	P value
Normal-normal	783	23.3 (21.7–25.0)	Ref	-
Normal-overweight	1071	28.2 (26.6–30.0)	1.27 (1.10–1.46)	0.001
Normal-obese	554	40.6 (37.3–44.1)	1.73 (1.48–2.02)	<0.001
Overweight-normal	50	22.2 (16.8–29.3)	1.06 (0.76–1.47)	0.752
Overweight-overweight	333	22.8 (20.5–25.4)	1.12 (0.93–1.35)	0.229
Overweight-obese	539	38.8 (35.6–42.2)	2.00 (1.71–2.34)	<0.001
Obese-normal	-	-	-	-
Obese-overweight	31	26.8 (18.9–38.2)	1.13 (0.68–1.87)	0.634
Obese-obese	238	40.0 (35.2–45.4)	2.08 (1.73–2.51)	<0.001

^aWeight change categories based on BMI at age 25 (young adulthood) and BMI 10 years prior to the survey (midlife). Weight change categories are defined in Table S1.

^bIncident arthritis conditions reflects the number of new arthritis conditions that occurred over the 10-years of follow-up from the recalled midlife weight measure to the time of survey.

^cArthritis conditions incidence rate per 1,000 person-years. Incidence rates are unadjusted.

^dHazard of developing an arthritis condition, using normal-normal as the reference group. The Cox proportional hazard model was sample weighted and adjusted for categorical age at the midlife measure, gender, race/ethnicity, education level at survey, smoking status at the midlife measure, and survey year.

- indicates HR was suppressed because there were less than 10 incident cases in this group.