Table 1.
Individual exposures to potential sources of nontuberculous mycobacteria and their association with incident NTM infections
| Factor | Cases (N = 48), n (%) | Controls (N = 85), n (%) | Odds Ratio (95% CI)* | Adjusted OR (95% CI) |
|---|---|---|---|---|
| Demographics | ||||
| Females | 28 (58) | 49 (58) | 1.6 (0.5–5.7) | |
| Residential exposure | ||||
| Single-family house | 39 (81) | 54 (64) | 2.7 (1.0–7.1) | 4.2 (1.4–13.4) |
| Mobile home | 0 (0) | 5 (6) | NA | |
| Multiple-unit dwelling (apartment, condominium, or dormitory) | 9 (19) | 24 (28) | 0.7 (0.3–2.0) | |
| Moved to a new residence | 6 (13) | 19 (22) | 0.5 (0.2–1.6) | |
| Water exposure | ||||
| Residence water supply | ||||
| Municipal supply | 40 (89) | 70 (84) | 1.4 (0.4–5.1) | |
| Artesian well water | 0 (0) | 2 (2) | NA | |
| Closed/pumped well water | 5 (11) | 11 (13) | 0.9 (0.2–3.7) | |
| Filtered home drinking water | 15 (31) | 16 (19) | 1.7 (0.8–3.9) | |
| Showering | 0.6 (0.2–1.9) | |||
| Never showered | 0 (0) | 0 (0) | ||
| Showered <1 time/d | 11 (23) | 19 (24) | ||
| Showered ≥1 time/d | 36 (77) | 61 (76) | ||
| Bathing | 1.2 (0.6–2.5) | |||
| Never took baths | 28 (58) | 57 (67) | ||
| Bathed <1 time/d | 17 (35) | 21 (25) | ||
| Bathed ≥1 time/d | 3 (6) | 7 (8) | ||
| Drinking water type | ||||
| Usually drank tap water | 30 (63) | 56 (67) | 1.0 (0.4–2.2) | |
| Usually drank bottled water | 17 (35) | 22 (26) | 1.4 (0.6–3.5) | |
| Drinking tap water | ||||
| Tap at home | 1.1 (0.6–1.8) | |||
| Never drank tap water at home | 9 (19) | 17 (20) | ||
| Drank tap water at home <3 times/d | 17 (35) | 26 (31) | ||
| Drank tap water at home ≥3 times/d | 22 (46) | 42 (49) | ||
| Tap outside home | 1.4 (0.8–2.4) | |||
| Never drank tap water outside home | 24 (50) | 47 (55) | ||
| Drank tap water outside home <3 times/d | 17 (35) | 28 (33) | ||
| Drank tap water outside home ≥3 times/d | 7 (15) | 10 (12) | ||
| Drinking bottled water | 1.2 (0.7–2.1) | |||
| Never drank bottled water | 27 (56) | 54 (64) | ||
| Drank <3 glasses/d bottled water | 9 (19) | 15 (18) | ||
| Drank ≥3 glasses/d bottled water | 12 (25) | 16 (19) | ||
| Brushing teeth | 0.5 (0.2–1.4) | |||
| Brushed teeth with warm tap water | 9 (19) | 22 (26) | ||
| Brushed teeth with cold tap water | 39 (81) | 63 (74) | ||
| Gargled with tap water | 18 (38) | 27 (32) | 1.1 (0.5–2.5) | |
| Plumbing work done at home | 6 (13) | 3 (4) | 4.1 (0.8–21.0) | |
| Tap water at home appeared rusty/unclear | 12 (25) | 13 (15) | 2.9 (1.0–8.9) | 3.5 (1.02–11.7) |
| Ingested water from pond, stream, or lake | 7 (15) | 9 (10) | 2.2 (0.5–8.9) | |
| Swimming | ||||
| Outdoor pools | 1.3 (0.7–2.4) | |||
| Never swam in outdoor pools | 32 (67) | 60 (71) | ||
| Swam in outdoor pool <1 time/wk | 10 (21) | 15 (18) | ||
| Swam in outdoor pool ≥1 time/wk | 6 (13) | 9 (11) | ||
| Ever swam in outdoor pools | 16 (33) | 24 (29) | 1.6 (0.7–3.7) | |
| Indoor pools | 1.8 (0.8–4.1) | |||
| Never swam in indoor pools | 39 (81) | 80 (94) | ||
| Swam in indoor pool <1 time/wk | 7 (15) | 2 (2) | ||
| Swam in indoor pool ≥1 time/week | 2 (4) | 3 (4) | ||
| Ever swam in indoor pools | 9 (19) | 5 (6) | 4.2 (1.1–16.1) | 5.9 (1.3–26.1) |
| Jacuzzis | 1.9 (0.9–4.3) | |||
| Never used Jacuzzis | 32 (71) | 67 (82) | ||
| Used Jacuzzis <1 time/wk | 8 (18) | 14 (17) | ||
| Swam in Jacuzzis ≥1 time/wk | 5 (11) | 1 (1) | ||
| Ever used Jacuzzis | 13 (29) | 15 (18) | 1.7 (0.6–4.5) | |
| Ponds, streams, lakes | 1.6 (0.7–3.4) | |||
| Never swam in ponds, streams, or lakes | 35 (80) | 70 (89) | ||
| Swam in ponds, streams, or lakes <1 time/wk | 6 (14) | 5 (6) | ||
| Swam in ponds, streams, or lakes ≥1 time/wk | 3 (7) | 4 (5) | ||
| Gulf, ocean | 1.2 (0.6–2.5) | |||
| Never swam in gulf or ocean | 35 (76) | 69 (83) | ||
| Swam in gulf or ocean <1 time/wk | 10 (22) | 10 (12) | ||
| Swam in gulf or ocean ≥1 time/wk | 1 (2) | 4 (5) | ||
| Soil exposure | ||||
| Planting or digging in soil | 11 (23) | 19 (23) | 0.7 (0.3–1.7) | |
| Watering | 14 (29) | 19 (23) | 1.4 (0.6–3.5) | |
| Weeding | 12 (25) | 12 (14) | 1.5 (0.6–4.0) | |
| Composting | 1 (2) | 2 (2) | 0.8 (0.1–8.9) | |
| Mowing grass, cutting hay | 1 (25) | 6 (60) | 1.0 (0.1–16.0) | |
| Vapor exposure | ||||
| Air conditioner type | ||||
| Central air | 19 (76) | 38 (78) | 1.1 (0.2–5.8) | |
| Casement (window) unit | 12 (44) | 19 (34) | 2.6 (0.5–14.3) | |
| Humidifier or vaporizer | ||||
| Cold, portable, or room | 6 (55) | 10 (42) | Undefined | |
| Hot, portable, or room | 2 (18) | 6 (25) | 0.4 (0.03–4.4) | |
| Supplemental oxygen with in-line humidifier | 3 (75) | 8 (42) | 2.6 (0.2–29.1) | |
| Nebulizer-related exposure | ||||
| Received inhaled or nebulized therapy (not MDI) | 40 (83) | 71 (84) | 0.7 (0.2–2.2) | |
| Nebulizer type | ||||
| Compressed air | 35 (97) | 65 (94) | 2.6 (0.2–29.1) | |
| Ultrasonic | 2 (6) | 10 (14) | 0.2 (0.02–1.5) | |
| Mixing inhaled therapy with fluids | ||||
| Sterile saline | 17 (35) | 38 (45) | 0.6 (0.3–1.3) | |
| Sterile water | 3 (17) | 8 (20) | 1.2 (0.2–8.6) | |
| Tap water, unboiled | 1 (6) | 0 (0) | Undefined | |
| Replacing nebulizer (compressed air) or medication cup (ultrasonic) | 1.6 (0.5–5.0) | |||
| Never replaced | 7 (18) | 14 (21) | ||
| Replaced <1 time/d | 28 (74) | 50 (75) | ||
| Replaced ≥1 time/d | 3 (8) | 3 (4) | ||
| Cleaning nebulizer | ||||
| Disposable parts | 1.2 (0.7–1.9) | |||
| Never cleaned | 8 (18) | 18 (22) | ||
| Cleaned disposable parts <1 time/d | 9 (20) | 21 (26) | ||
| Cleaned disposable parts ≥1 time/d | 28 (62) | 43 (52) | ||
| Nondisposable parts | 0.6 (0.3–1.1) | |||
| Never cleaned | 27 (63) | 40 (53) | ||
| Cleaned nondisposable parts <1 time/d | 14 (33) | 24 (32) | ||
| Cleaned nondisposable parts ≥1 time/d | 2 (5) | 11 (15) | ||
| Fluid used most often to clean nebulizer | ||||
| Sterile saline | 0 (0) | 1 (1) | Undefined | |
| Sterile water | 0 (0) | 1 (1) | Undefined | |
| Boiled bottled water | 1 (2) | 2 (2) | 2.4 (0.2–39.7) | |
| Unboiled bottled water | 1 (2) | 0 (0) | Undefined | |
| Boiled tap water | 4 (9) | 13 (15) | 0.5 (0.1–1.9) | |
| Unboiled tap water | 27 (61) | 50 (60) | 0.9 (0.4–2.4) | |
| Detergent or soap | 10 (23) | 19 (22) | 1.1 (0.5–2.7) | |
| Disinfecting solution | 40 (91) | 78 (94) | 0.9 (0.2–4.2) | |
| Vinegar | 13 (30) | 22 (26) | 1.1 (0.4–2.6) | |
| Allowed nebulizer to dry between uses | 35 (90) | 63 (90) | 1.1 (0.3–4.8) | |
| Other procedures | ||||
| Nasal washes | 11 (23) | 14 (17) | 1.5 (0.5–4.1) | |
| Bronchoscopy | 0 (0) | 0 (0) | NA |
Definition of abbreviations: CI = confidence interval; MDI = metered-dose inhaler; NA = not applicable; NTM = nontuberculous mycobacterial; OR = odds ratio.
*
For nonordinal variables, the reference group for any given category was all those who reported “no” for a particular category. For ordinal variables, the odds ratio was estimated from a fitted logistic regression model, with the odds corresponding to each level of increase. Proportions and odds ratios are reported only for those who had valid values (i.e., nonmissing) for the reported exposures.