Table 2.
Childhood Residential Factors, Potential Pesticide Exposures, and Association With Rheumatoid Arthritis, Sister Study, United States, 2004–2009
| Longest Residence to Age 14 Years | Case Patients With RA (n = 424) | Noncase Patients (n = 48,919) | Age Adjusted | Fully Adjusteda | ||||
|---|---|---|---|---|---|---|---|---|
| No. | % | No. | % | OR | 95% CI | OR | 95% CI | |
| Residential areab | ||||||||
| Urban | 106 | 25 | 10,921 | 23 | 1.2 | 0.93, 1.6 | 1.2 | 0.89, 1.6 |
| Suburban/other | 98 | 23 | 13,488 | 28 | 1.0 | Referent | 1.0 | Referent |
| Small town | 107 | 25 | 12,467 | 26 | 1.1 | 0.84, 1.5 | 1.1 | 0.81, 1.5 |
| Rural | 111 | 26 | 11,190 | 23 | 1.3 | 0.95, 1.7 | 1.2 | 0.91, 1.6 |
| Near or on a farm or orchardc | ||||||||
| Not a farm/not near a farm | 242 | 64 | 28,112 | 64 | 1.0 | Referent | 1.0 | Referent |
| Near a farm | 53 | 14 | 6,024 | 14 | 1.0 | 0.77, 1.4 | 1.1 | 0.82, 1.5 |
| Used to be a farm | 21 | 6 | 2,908 | 7 | 0.87 | 0.55, 1.4 | 0.96 | 0.60, 1.5 |
| On an active farm | 65 | 17 | 6,822 | 16 | 1.0 | 0.76, 1.3 | 1.0 | 0.75, 1.4 |
| Source of drinking waterd | ||||||||
| City/town water supply | 295 | 71 | 35,637 | 75 | 1.0 | Referent | 1.0 | Referent |
| Private/community well, other | 123 | 29 | 11,972 | 25 | 1.2 | 0.96, 1.5 | 1.2 | 0.92, 1.4 |
| Residential pesticide usee | ||||||||
| Never | 275 | 73 | 33,515 | 76 | 1.0 | Referent | 1.0 | Referent |
| Ever | 102 | 27 | 10,340 | 24 | 1.3 | 1.0, 1.6 | 1.2 | 0.92, 1.6 |
| Frequency | ||||||||
| Less than monthly | 62 | 17 | 7,401 | 17 | 1.1 | 0.85, 1.5 | 1.1 | 0.85, 1.5 |
| Monthly | 27 | 7 | 1,765 | 4 | 2.1 | 1.4, 3.1 | 1.6 | 1.0, 2.6 |
| At least weekly | 9 | 2 | 662 | 2 | 1.7 | 0.88, 3.4 | 1.4 | 0.69, 2.9 |
| Personally applied | ||||||||
| Never | 84 | 22 | 9,176 | 21 | 1.2 | 0.95, 1.6 | 1.2 | 0.91, 1.5 |
| Some of the time | 10 | 3 | 971 | 2 | 1.4 | 0.72, 2.6 | 1.1 | 0.53, 2.2 |
| Most or all the time | 8 | 2 | 171 | 0 | 6.1 | 3.0, 12.6 | 4.7 | 2.2, 10.0 |
| Combined exposure levelf | ||||||||
| Indirect and infrequent | 53 | 13 | 6,746 | 14 | 1.1 | 0.78, 1.4 | 1.1 | 0.80, 1.5 |
| Indirect and frequent | 27 | 6 | 1,947 | 4 | 1.8 | 1.2, 2.7 | 1.5 | 0.97, 2.4 |
| Direct and infrequent | 9 | 2 | 647 | 1 | 1.9 | 0.95, 3.6 | 1.6 | 0.83, 3.9 |
| Direct and frequent | 9 | 2 | 476 | 1 | 2.5 | 1.3, 4.9 | 1.8 | 0.82, 3.9 |
| P for trend | 0.0001 | 0.013 | ||||||
Abbreviations: CI, confidence interval; OR, odds ratios; RA, rheumatoid arthritis.
a Models were adjusted for age, race or ethnicity, college education, pack-years of smoking, and childhood socioeconomic status score (numbers are reduced because of missing covariate data for 37 case patients and 3,232 noncase patients).
b Numbers do not add to the total number of cases because of missing data for 2 case patients (0.5%) and 853 noncase patients (2%). Percentages do not add to 100 because of rounding.
c Numbers do not add to the total number of cases because of missing data on childhood farm residence for 43 case patients (10%) and 5,053 noncase patients (10%). Percentages are based on nonmissing data and do not add to 100 because of rounding.
d Numbers do not add to the total number of cases because of missing data for 6 case patients (1%) and 1,310 noncase patients (3%). Percentages are based on nonmissing data.
e Numbers do not add to the total number of cases because of missing data on childhood residential pesticide use for 47 case patients (11%) and 5,064 noncase patients (10%), on frequency for an additional 4 case patients (1%) and 512 noncase patients (1%), and on personal use for an additional 22 noncase patients (0%). Percentages are based on nonmissing data.
f Direct refers to having applied pesticide personally some or most of the time; indirect refers to others having applied pesticide; frequent refers to having applied pesticide at least monthly; infrequent refers to having applied pesticide less often than monthly.