The Impact of Body Mass Index and Weight Changes on Disability Transitions and Mortality in Brazilian Older Adults

Table 4

Relative risk ratios of the impact of body mass index categories and body mass index changes on disability transitions, São Paulo, Brazil—2000–2006.

Variables	ADL		𝑃	IADL		𝑃	NAGI		𝑃
	RRR^a	95% CI		RRR	95% CI		RRR	95% CI
Incidence of disability (reference = remain free of disability)
Age	1.10	[1.07,1.13]	***	1.11	[1.08,1.15]	***	1.05	[1.01,1.09]	*
Female	1.75	[1.04,2.94]	*	1.53	[0.88,2.65]		2.44	[1.44,4.12]	**
Smoking status
Former smoker	0.85	[0.53,1.38]		1.14	[0.67,1.95]		1.47	[0.87,2.50]
Current smoker	1.38	[0.71,2.70]		1.45	[0.67,3.16]		0.97	[0.56,1.69]
Number of chronic conditions	1.56	[1.32,1.86]	***	1.33	[1.12,1.59]	**	1.25	[0.92,1.68]
Schooling	0.97	[0.88,1.07]		0.92	[0.82,1.03]		0.90	[0.80,1.01]
Live alone	0.85	[0.50,1.44]		0.60	[0.34,1.08]		1.01	[0.42,2.41]
BMI categories
Underweight	0.92	[0.48,1.77]		1.73	[1.05,2.84]	*	0.93	[0.49,1.79]
Overweight	0.72	[0.36,1.44]		1.39	[0.67,2.88]		1.87	[0.87,3.99]
Obese	1.99	[1.10,3.57]	*	2.38	[1.61,3.52]	***	1.22	[0.66,2.27]
BMI change
Loss	1.23	[0.76,2.00]		0.99	[0.62,1.60]		0.85	[0.49,1.48]
Gain	2.30	[1.03,5.12]	*	1.97	[0.97,4.01]		2.15	[1.20,3.85]	*
𝑁	800			737			389
BIC′	27.46			9.40			28.56
Recovery from disability (reference = remain with disability)
Age	0.92	[0.87,0.98]	*	0.93	[0.88,0.99]	*	0.95	[0.91,0.99]	*
Female	0.43	[0.13,1.47]		0.41	[0.11,1.58]		0.53	[0.28,1.01]
Smoking status
Former smoker	0.34	[0.09,1.30]		1.40	[0.60,3.29]		1.46	[0.74,2.87]
Current smoker	1.11	[0.29,4.17]		0.69	[0.10,4.70]		0.97	[0.38,2.44]
Number of chronic conditions	0.64	[0.45,0.90]	*	0.94	[0.68,1.29]		0.60	[0.46,0.80]	***
Schooling	1.05	[0.87,1.28]		1.05	[0.82,1.34]		1.03	[0.87,1.22]
Live alone	0.50	[0.12,2.02]		1.03	[0.22,4.85]		3.27	[1.63,6.57]	**
BMI categories
Underweight	0.49	[0.12,2.04]		0.16	[0.02,1.40]		0.71	[0.26,1.88]
Overweight	0.89	[0.27,2.88]		0.76	[0.18,3.20]		0.86	[0.31,2.36]
Obese	0.42	[0.17,1.05]		0.68	[0.22,2.07]		0.43	[0.21,0.86]	*
BMI change
Loss	0.52	[0.23,1.19]		0.53	[0.21,1.35]		1.07	[0.61,1.89]
Gain	0.18	[0.05,0.68]	*	0.64	[0.15,2.73]		0.53	[0.21,1.37]
𝑁	161			224			572
BIC′	31.87			91.45			85.22

ADL: activities of daily living; IADL: instrumental activities of daily living; RRR: relative risk ratio; CI: confidence interval; BMI: body mass index.
^aRelative risk ratios were adjusted by smoking status. Remaining free of disability is the reference category for those who started without disability, and remaining with disability is the reference category for those who had disability in the baseline. Normal weight is the reference category for BMI. Stable weight is the baseline category for weight change. Results for lost in the followup were omitted (available upon request).
*** 𝑃<0.001; **𝑃<0.05; *𝑃<0.10.