Table 3

Effect of Baseline Characteristics on Time to Developing Incident Multimorbidity Between 2002-2003 and 2012-2013: Complementary Log-Log Models

Characteristic	No Condition in 2002-2003 (n = 1,477) and ≥2 Incident Conditions (Multimorbidity) by 2012-2013		Any Number of Conditions in 2002- 2003 (n = 4,564) and ≥1 Incident Conditions by 2012-2013

	HR (95% CI)	P Value	HR (95% CI)	P Value
Age, y	Linear trend	<.001	Linear trend	<.001
50-54	1.00 [Reference]	…	1.00 [Reference]	…
55-59	1.44 (1.05-1.99)^a	.025^a	1.29 (1.14-1.45)^a	<.001^a
60-64	1.85 (1.31-2.61)^a	<.001^a	1.42 (1.25-1.62)^a	<.001^a
65-69	2.93 (2.08-4.13)^a	<.001^a	1.49 (1.31-1.70)^a	<.001^a
≥70	2.58 (1.83-3.64)^a	<.001^a	1.49 (1.31-1.70)^a	<.001^a
Female (vs male)	1.14 (0.86-1.50)	.360	1.10 (0.99-1.21)	.072
Wealth quintiles	Linear trend	.001^a	Linear trend	.002^a
1 Wealthiest	1.00 [Reference]	…	1.00 [Reference]	…
2	1.27 (0.89-1.80)	.185	0.97 (0.85-1.10)	.620
3	1.41 (1.00-1.97)	.049	1.08 (0.95-1.23)	.215
4	1.23 (0.85-1.78)	.269	1.11 (0.97-1.26)	.120
5 Least wealthy	2.19 (1.50-3.19)^a	<.001^a	1.22 (1.06-1.39)^a	.005^a
Educational attainment	Linear trend	.058	Linear trend	.923
Degree /higher ed	1.00 [Reference]	…	1.00 [Reference]	…
Intermediate	0.95 (0.73-1.23)	.701	1.04 (0.94-1.15)	.413
No qualification	0.73 (0.53-1.00)	.051	1.00 (0.89-1.12)	.993
Lives alone (vs cohabits)	0.93 (0.71-1.21)	.580	1.08 (0.98-1.19)	.128
BMI category (2004)	Linear trend	<.001^a	Linear trend	<.001^a
Underweight or normal weight	1.00 [Reference]	…	1.00 [Reference]	…
Overweight	1.15 (0.87-1.52)	.339	1.10 (0.99-1.21)	.070
Obese	1.92 (1.43-2.59)^a	<.001^a	1.27 (1.14-1.42)^a	<.001^a
Smoking behavior
Never smoked	1.00 [Reference]	…	1.00 [Reference]	…
Smoked in past	1.12 (0.88-1.43)	.359	1.09 (1.00-1.19)	.050
Current smoker	1.22 (0.87-1.70)	.248	1.21 (1.07-1.36)^a	.002^a
Physical activity	Linear trend	.031^a	Linear trend	.004^a
High	1.00 [Reference]	…	1.00 [Reference]	…
Medium	1.3 (1.00-1.70)	.051	1.08 (0.97-1.19)	.149
Low	1.43 (1.02-2.00)^a	.039^a	1.19 (1.06-1.35)^a	.004^a
Social detachment (vs none)	1.16 (0.77-1.72)	.480	1.07 (0.93-1.22)	.360
External locus of control (vs internal)	1.41 (1.10-1.82)^a	.007^a	1.13 (1.03-1.23)^a	.010^a

BMI = body mass index; HR = hazard ratio.
Note: Complementary log-log models are the discrete time equivalent of Cox proportional hazards models for continuous time. The reference category for each covariate is the first category listed. A HR >1.00 indicates increased risk, whereas an HR of <1.00 indicates reduced risk. Models were corrected for differential nonresponse using longitudinal sample weighting.
↵a Significant association.