Table 1. Early life risk factors for asthma among schoolchildren enrolled in a case-control study between 2015–17 (N = 1,670).
| Risk factors | Asthma cases N = 555 |
Non-asthma controls N = 1115 | Adj. OR (95% CI)* |
|---|---|---|---|
| Age, years, Mean (Range) | 11.42 (3.26) | 10.98 (3.05) | 1.07 (1.03–1.11) |
| Sex: Girls (933) | 294 (53.0) | 639 (57.3) | 0.79 (0.63–0.99) |
| Mother’s history of asthma [m = 164] | |||
| Yes (102) | 61 (12.0) | 41 (4.1) | 3.05 (1.97–4.71) |
| Father’s history of asthma [m = 175] | |||
| Yes (85) | 65 (12.8) | 20 (2.0) | 6.64 (3.90–11.30) |
| Fathers’ highest education level | |||
| None/Primary (437) | 99 (17.8) | 338 (30.3) | 1 |
| Secondary (594) | 193 (34.8) | 401 (36.0) | 1.61 (1.20–2.16) |
| Tertiary (639) | 263 (47.4) | 376 (33.7) | 2.32 (1.71–3.16)† |
| Mothers’ highest education attained [m = 4] | |||
| None/Primary (577) | 158 (28.6) | 419 (37.6) | 1 |
| Secondary (601) | 185 (33.4) | 416 (37.4) | 1.11 (0.85–1.44) |
| Tertiary (488) | 210 (38.0) | 278 (25.0) | 1.85 (1.38–2.48)† |
| Child’s residence at birth | |||
| Rural (352) | 74 (13.3) | 278 (24.9) | 1 |
| Town (1,169) | 412 (74.2) | 757 (67.9) | 2.16 (1.60–2.92) |
| City (149) | 69 (12.5) | 80 (7.2) | 2.79 (1.79–4.35)† |
| Child’s residence for most of 0–5 years | |||
| Rural (337) | 72 (13.0) | 265 (23.8) | 1 |
| Town (1,247) | 434 (78.2) | 813 (72.9) | 1.96 (1.44–2.66) |
| City (86) | 49 (8.8) | 37 (3.3) | 3.74 (2.19–6.39)† |
| Maternal regular contact with farm animals during pregnancy [m = 252] | |||
| Yes (500) | 152 (30.2) | 348 (38.0) | 0.82 (0.64–1.06) |
| Maternal cigarette smoking during pregnancy [m = 302] | |||
| Yes (36) | 13 (2.7) | 23 (2.6) | 1.07 (0.51–2.22) |
| Breast feeding duration [m = 402] | |||
| <1 year (328) | 114 (25.3) | 214 (26.2) | 1 |
| >1 year (940) | 337 (74.7) | 603 (73.8) | 1.12 (0.85–1.49) |
| Allergic rhinitis ever | |||
| Yes (862) | 429 (77.3) | 433 (38.8) | 5.53 (4.31–7.09) |
| Allergic conjunctivitis ever | |||
| Yes (766) | 361 (65.0) | 405 (36.3) | 3.12 (2.50–3.90) |
| Eczema ever | |||
| Yes (264) | 126 (22.7) | 138 (12.4) | 2.08 (1.56–2.77) |
| Urticarial rash ever | |||
| Yes (569) | 222 (40.0) | 347 (31.1) | 1.42 (1.13–1.79) |
| Presence of a BCG scar on child’s arm at enrolment [m = 83] | |||
| Yes (1,315) | 413 (78.4) | 902 (85.1) | 0.67 (0.51–0.89) |
Adj. OR = adjusted odds ratio; CI = confidence interval; N = number; m = missing; number (%) in 2nd and 3rd column unless indicated otherwise.
*adjusted for child’s age, sex, residence at birth and father’s education level.
†Test for trend p-value<0.0001. For parental history of allergy, 6.6% mothers and 3.4% fathers responded by telephone.