A Prospective Study of Lupus and Rheumatoid Arthritis in Relation to Deployment in Support of Iraq and Afghanistan: The Millennium Cohort Study
Table 3
Odds of newly reported rheumatoid arthritis and military deployment, the Millennium Cohort Study ().
Characteristics
Unadjusted
Final model*
Confirmed case model†
OR
95% CI
AOR‡
95% CI
AOR‡
95% CI
Deployment§
Nondeployed
1.00¶
1.00¶
1.00¶
Deployed without combat
0.47
0.39–0.56
0.59
0.48–0.73
0.70
0.33–1.49
Deployed with combat#
0.69
0.59–0.81
0.74
0.62–0.88
0.83
0.38–1.77
Sex
Male
1.00¶
1.00¶
1.00¶
Female
1.16
1.02–1.31
1.26
1.08–1.47
1.96
0.88–4.37
Birth year
Before 1960
1.00¶
1.00¶
1.00¶
1960–1969
0.72
0.63–0.82
0.64
0.55–0.74
0.94
0.30–2.95
1970–1979
0.33
0.27–0.39
0.31
0.26–0.38
0.32
0.09–1.20
1980 and later
0.29
0.22–0.39
0.26
0.19–0.35
0.37
0.08–1.78
Race/ethnicity
Non-Hispanic white
1.00¶
1.00¶
1.00¶
Non-Hispanic black
2.27
1.97–2.62
1.77
1.51–2.08
0.58
0.21–1.60
Hispanic
1.49
1.20–1.85
1.40
1.11–1.76
1.17
0.41–3.36
Other
0.92
0.74–1.13
1.00
0.79–1.27
1.26
0.42–3.78
Education
High school or less
1.00¶
1.00¶
1.00¶
Some college
1.67
1.47–1.91
1.21
1.05–1.39
1.91
0.92–3.94
Bachelor’s or higher degree
0.88
0.76–1.01
1.10
0.93–1.30
1.57
0.64–3.88
Marital status
Married
1.00¶
Not married
0.98
0.87–1.11
Service component
Active duty
1.00¶
1.00¶
1.00¶
Reserve/Guard
0.83
0.74–0.93
0.73
0.64–0.83
0.14
0.02–1.35
Military pay grade
Enlisted
1.00¶
1.00¶
1.00¶
Officer
0.45
0.39–0.53
0.60
0.48–0.74
0.17
0.05–0.61
Service branch
Army
1.00¶
1.00¶
Air Force
0.63
0.55–0.73
0.79
0.67–0.92
Marine Corps
0.71
0.53–0.96
1.01
0.74–1.37
Navy/Coast Guard
0.67
0.57–0.79
0.74
0.62–0.89
Occupation
Functional support
1.00¶
1.00¶
1.00¶
Combat specialist
0.80
0.66–0.96
1.09
0.90–1.32
0.78
0.26–2.35
Health care specialist
0.60
0.48–0.76
0.66
0.52–0.85
0.50
0.16–1.55
Electrical/mechanical
1.03
0.85–1.24
1.07
0.87–1.36
1.12
0.46–2.74
Service support
1.19
0.97–1.44
1.11
0.91–1.36
1.52
0.56–4.12
Other
0.87
0.74–1.02
1.00
0.85–1.19
0.40
0.16–0.97
Body mass index (kg/m2)
Normal/Underweight (<25)
1.00¶
1.00¶
1.00¶
Overweight (25 to <30)
1.34
1.16–1.54
1.11
0.95–1.29
0.77
0.38–1.56
Obese (≥30)
2.41
2.07–2.80
1.41
1.20–1.67
1.20
0.49–2.91
Smoking status
Nonsmoker
1.00¶
1.00¶
1.00¶
Past smoker
1.39
1.22–1.58
1.13
0.99–1.30
1.63
0.84–3.14
Current smoker
1.54
1.33–1.80
1.19
1.02–1.40
0.56
0.20–1.56
Alcohol misuse**
No
1.00¶
Yes
1.18
1.04–1.36
Mental component score
>75th percentile
1.00¶
1.00¶
1.00¶
>50th to 75th percentile
0.73
0.62–0.85
0.89
0.75–1.06
0.72
0.35–1.48
>25th to 50th percentile
0.87
0.75–1.02
1.04
0.88–1.23
0.73
0.36–1.49
0 to 25th percentile
1.67
1.46–1.92
1.64
1.42–1.91
0.85
0.42–1.70
Physical component score
>75th percentile
1.00¶
1.00¶
1.00¶
>50th to 75th percentile
1.40
1.05–1.86
1.38
1.02–1.88
1.34
0.37–4.83
>25th to 50th percentile
2.99
2.30–3.90
2.72
2.06–3.61
2.56
0.78–8.35
0 to 25th percentile
12.25
9.60–15.63
9.03
6.95–11.74
7.89
2.48–25.10
Chemical/biological warfare agents
No
1.00¶
1.00¶
1.00¶
Yes, 1 or more times
0.98
0.85–1.12
1.47
1.22–1.78
1.43
0.49–4.18
Hazards requiring personal protective equipment
No
1.00¶
Yes
0.96
0.85–1.07
Do not know
1.59
1.17–2.18
Routine skin contact with paint, solvents, substances
No
1.00¶
Yes
1.39
1.24–1.56
Do not know
1.74
1.38–2.19
Microwaves (excluding microwave ovens)
No
1.00¶
1.00¶
1.00¶
Yes
1.44
1.26–1.64
1.14
0.99–1.31
0.80
0.36–1.78
Do not know
1.63
1.38–1.92
1.25
1.05–1.50
1.58
0.60–4.16
Pesticides (creams, sprays, uniform treatments)
No
1.00¶
Yes
1.39
1.24–1.57
Do not know
1.36
1.13–1.64
Pesticides (environment, living facilities)
No
1.00¶
Yes
1.47
1.30–1.65
Do not know
1.22
1.04–1.45
Time (years)
1.44
1.40–1.48
1.31
1.27–1.35
1.19
0.99–1.44
AOR, adjusted odds ratio; CI, confidence interval; OR, odds ratio.
*Final model established by removing nonsignificant, nonconfounding covariates from the full model. †Confirmed cases model is among active-duty, nonseparated participants. There were not enough confirmed cases for service branch to be tested in the model. ‡Adjusted odds ratios and associated 95% confidence intervals are adjusted for all other variables in the table. §Deployed in support of the operations in Iraq and Afghanistan. ¶Indicates reference category. #Self-report of personally witnessing or being exposed to a person’s death due to war or disaster, physical abuse, dead and/or decomposing bodies, maimed soldiers or civilians, prisoners of war, or refugees.
**Alcohol misuse is defined as at least 1 positive response to the CAGE questions (i.e., cutting down, annoyance by criticism, guilty feeling, and eye-openers) [32, 33].
