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. Author manuscript; available in PMC: 2016 May 1.
Published in final edited form as: J Epidemiol Community Health. 2015 Jan 6;69(5):416–422. doi: 10.1136/jech-2014-204248
Hazard Ratios (95% CI)
Socioeconomic Status M1:
Base model
from Table 3
that excludes
behavioral
factors
(N=3,617) 		M2:
Behavioral
Factors
lagged by
one Wave
(N=3,115)a 		M3:
Inclusion of
baseline health
status and
behavioral
factors
(N=3,617)b 		M4:
Inverse
probability
weighted models
(N=3,084)c
Education (0–11 vs. 16+ yrs.) 1.88
(1.48, 2.39)		 1.56
(1.20, 2.04)		 1.34
(1.05, 1.71)		 1.69
(1.03, 2.76)
1986 Income (<$10k vs. $30k+) 2.09
(1.72, 2.56)		 1.61
(1.35, 1.90)		 1.51
(1.23, 1.86)		 1.78
(1.09, 2.90)

Note: Education and 1986 income estimated on separate models. All models include adjustments for age at baseline, sex, and race. Mortality linkage through 2011. The reference category for education is 16+ years of schooling. The reference category for income is $30,000+.

a

M2 restricted to waves 2 (1989), 3 (1994), and 4 (2001/2). Model includes time-varying behavioral factors (cigarette smoking, physical activity, BMI, alcohol use) lagged by one wave.

b

M3 based on all waves of data and includes an adjustment for self-rated health (excellent, very good, good, fair, poor) and functional health as reported at baseline (wave 1,1986). Functional health is coded according to degree of impairment: (1) Most impairment (in bed most of day or difficulty bathing self), (2) Moderate impairment (cannot climb a few flights of stairs or cannot walk several blocks), (3) Low impairment (difficulty or cannot do heavy work around house), and (4) No impairment (little to some difficulty doing heavy work around the house). Behavioral factors (cigarette smoking, physical activity, BMI, alcohol use) were included as time-varying variables.

c
M4 is estimated with an inverse probability-weighted marginal structural model using data from waves 2,3, and 4. M4 equation included controls for fixed confounders (age, race, sex) and the time-varying behavioral factors (cigarette smoking, physical activity, BMI, alcohol use). Observations with inverse probability weights in the top one percentile were excluded. The inverse probability weight was constructed by the formula (wiE * wiI * witO * witS * witPA* witALC* wiACL), where the subscripts i refers to an individual and t refers to survey wave, and:
  • (1)
    wiE = Pr(E=ei/Pr(E=ei | C=ci)
  • (2)
    wiI = Pr(I=ii | E=ei/ Pr(I=ii | E=ei, C=Ci)
  • (3)
    witO=Pr(O=Oit | E=ei, I=ii)/Pr(O=Oit | O=Oi(t-1), E=ei, I=iiC=ci, R=ri(t–1))
  • (4)
    witS=Pr(S=Sit | E=ei, I=ii)/Pr(S=Sit | S=Si(t–1), O=Oi(t–1), E=ei, I=iiC=ci, R=ri(t–1))
  • (5)
    witPA=Pr(PA=pait | E=ei, I=ii)/Pr(PA=pait | PA=pai(t–1), S=Si(t–1), O=Oi(t–1), E=ei, I=iiC=ci, R=ri(t–1))
  • (6)
    witALC=Pr(ALC=alcit | E=ei, I=ii)/Pr(ALC=alcit | ALC=alci(t–1), PA=pai(t–1), S=Si(t–1), O=Oi(t–1), E=ei, I=iiC=ci, R=ri(t–1))
  • (7)
    wiACL=American Changing Lives (ACL) survey wave 1 weight;

E=educational attainment

I=income in 1986

C=fixed confounders (age at baseline, race, sex)

R=health status (self-rated health and functional health)

O=BMI (normal weight, overweight, obese)

S=current smoker

PA=physical activity (5 quintiles)

ALC=alcohol use (non-drinker, moderate drinker, heavy drinker)