Figures
- FIGURE 1
Cohort description and samples collected. IAP: indoor air pollution.
- FIGURE 2
Nasopharyngeal bacterial carriage at birth, 6 months and 1 year of life.
- FIGURE 3
Multivariate analysis of antenatal exposures and maternal nasopharyngeal bacterial carriage. PM10: particulate matter <10 µm in diameter; RR: risk ratio.
Tables
- TABLE 1
Maternal and infant characteristics
Mbekweni (black African) Newman (mixed ancestry) Total p-value Maternal characteristics Mothers 530 (54%) 452 (46%) 982 (100%) Age at enrolment years 26.9 (22.3, 31.6) 24.6 (21.3, 29.1) 25.8 (22.0, 30.6) <0.001 HIV-infected 193 (36%) 13 (3%) 206 (21%) <0.001 Unemployed 400 (75%) 325 (72%) 724 (74%) 0.205 SES quartile Lowest SES 157 (30%) 80 (18%) 237 (24%) <0.001 Low–moderate SES 150 (28%) 109 (24%) 259 (26%) Moderate–high SES 126 (24%) 127 (28%) 253 (26%) Highest SES 97 (18%) 136 (30%) 233 (24%) Household members 4 (3, 6) 5 (4, 7) 4 (3, 6) <0.001 Married/cohabiting 188 (35%) 194 (43%) 382 (39%) 0.017 Infant characteristics and birth outcomes Number of infants; sets of twins 534 (54%); 4 452 (46%); 0 986 (100%); 4 Female 280 (52%) 204 (45%) 484 (49%) 0.022 Gestation at delivery weeks 39 (38, 40) 39 (37, 40) 39 (38, 40) 0.032 Birthweight g 3180 (2810, 3460) 2990 (2630, 3340) 3080 (2720, 3415) <0.001 Weight-for-age z-score −0.4 (−1.3, 0.2) −0.7 (−1.4, −0.1) −0.6 (−1.3, 0.0) <0.001 Birthweight <2500 g 55 (10%) 83 (18%) 138 (14%) <0.001 Birth <37 weeks gestation 16 (3%) 19 (4%) 35 (4%) 0.314 Feeding at 6 months Exclusive breastfeeding 76 (14%) 66 (15%) 142 (14%) <0.001 Mixed 89 (17%) 170 (38%) 259 (26%) Not breastfeeding 369 (69%) 216 (48%) 585 (59%) Duration of exclusive breastfeeding months 1.1 (0.5, 3.0) 1.6 (0.9, 3.0) 1.4 (0.7, 3.0) 0.410 Day care attendance 6 months of age 17 (3%) 28 (6%) 45 (5%) 0.024 12 months of age 69 (13%) 90 (20%) 159 (16%) 0.003 Additional child under 5 years of age in household 455 (85%) 396 (88%) 851 (86%) 0.274 Respiratory infection in prior month 6 months of age 40 (7%) 37 (8%) 77 (8%) 0.685 12 months of age 29 (5%) 22 (5%) 51 (5%) 0.691 Antibiotic use in prior 6 months 6 months of age 25 (5%) 38 (8%) 63 (6%) 0.057 12 months of age 14 (3%) 13 (3%) 27 (3%) 0.957 Data are presented as median (interquartile range), unless otherwise stated. SES: socioeconomic score.
- TABLE 2
Home environment and exposures
Mbekweni Newman Total p-value Home environment Household dimensions# Has ≤2 dimensions 185 (38%) 121 (27%) 306 (33%) <0.001 Has >2 dimensions 302 (62%) 320 (73%) 622 (67%) Alternate fuel used (coal, wood, paraffin, gas) Cooking 133 (31%) 37 (10%) 170 (21%) <0.001 Heating 127 (29%) 7 (2%) 134 (16%) <0.001 Crowding Household size 4 (3, 6) 5 (4, 7) 4 (3, 6) <0.001 Persons per sleeping room 3 (2, 4) 3 (2, 5) 3 (2, 5) 0.010 Pollutants measured: antenatal PM10 g·m−3 (n=755) 32.0 (12.3, 64.2) 35.6 (12.8, 65.6) 33.4 (12.4, 65.6) 0.417 Above threshold 73 (19%) 65 (18%) 138 (18%) 0.853 NO2 µg·m−3 (n=747) 7.3 (2.6, 14.6) 7.1 (3.9, 11.3) 7.1 (3.4, 12.7) 0.494 Above threshold 16 (4%) 3 (1%) 19 (3%) 0.005 Benzene µg·m−3 (n=729) 4.6 (1.5, 17.9) 3.9 (1.8, 8.6) 4.3 (1.8, 11.0) 0.475 Above threshold 183 (47%) 147 (43%) 330 (45%) 0.244 Toluene µg·m−3 (n=729) 16.1 (5.9, 43.0) 17.4 (8.2, 46.5) 16.9 (7.2, 44.6) 0.282 Above threshold 36 (9%) 30 (9%) 66 (9%) 0.803 CO mg·m−3 (n=706) 0.0 (0.0, 5.1) 0.0 (0.0, 8.4) 0.0 (0.0, 7.6) 0.144 Above threshold 39 (10%) 42 (14%) 81 (11%) 0.095 Pollutants measured: postnatal PM10 g·m−3 (n=505) 30.0 (14.7, 49.7) 28.4 (10.5, 53.7) 29.3 (12.6, 52.5) 0.364 Above threshold 38 (16%) 36 (14%) 74 (15%) 0.499 NO2 µg·m−3 (n=532) 6.3 (2.9, 14.6) 5.3 (2.6, 11.3) 5.8 (2.6, 12.67) 0.119 Above threshold 6 (2%) 1 (0%) 7 (1%) 0.041 Benzene µg·m−3 (n=462) 2.8 (0.8, 14.4) 3.2 (1.5, 7.6) 3.1 (1.1, 9.5) 0.345 Above threshold 95 (39%) 75 (35%) 170 (37%) 0.426 Toluene µg·m−3 (n=462) 15.1 (4.9, 50.0) 15.9 (6.5, 51.7) 15.5 (5.9, 50.0) 0.342 Above threshold 24 (10%) 23 (11%) 47 (10%) 0.728 CO mg·m−3 (n=502) 0.0 (0.0, 0.0) 0.0 (0.0, 5.6) 0.0 (0.0, 0.0) 0.018 Above threshold 17 (7%) 30 (12%) 47 (9%) 0.026 Maternal antenatal tobacco smoking Number of mothers 530 451 981 Maternal urine cotinine (n=954) 512 442 <10 ng·mL−1, non-smoker 181 (35%) 47 (11%) 228 (24%) <0.001 10–499 ng·mL−1, passive/exposed 255 (50%) 155 (35%) 410 (43%) ≥500 ng·mL−1, active smoker 76 (15%) 240 (54%) 316 (33%) Infant urine cotinine Urine cotinine at birth or 6–10 weeks (n=763) 415 348 <10 ng·mL−1 184 (44%) 55 (16%) 239 (31%) <0.001 10–499 ng·mL−1 212 (51%) 208 (60%) 420 (55%) ≥500 ng·mL−1 19 (5%) 85 (24%) 104 (14%) Data are presented as median (interquartile range), unless otherwise stated. PM10: particulate matter <10 μm in diameter; NO2: nitrogen dioxide; CO: carbon monoxide. #: dimensions comprise type of home, building material, water supply, toilet facilities, kitchen type and ventilation in kitchen areas.
- TABLE 3
Multivariate analysis of postnatal exposures and infant nasopharyngeal bacterial carriage
S. aureus S. pneumoniae H. influenzae M. catarrhalis Gram negative bacilli Adj Adj2 Adj Adj2 Adj Adj2 Adj Adj2 Adj Adj2 PM10 6 months 0.98 (0.57–1.70) 0.95 (0.42–2.14) 0.96 (0.79–1.16) 0.96 (0.69–1.34) 1.09 (0.85–1.40) 1.68 (1.10– 2.57) 0.91 (0.70–1.18) 0.88 (0.57–1.35) 0.61 (0.19–1.95) 0.13 (0.02–1.05) 12 months 0.56 (0.13–2.48) 2.23 (0.40–12.35) 1.02 (0.87–1.20) 0.98 (0.72–1.35) 1.15 (0.88–1.51) 1.09 (0.69–1.73) 1.12 (0.90–1.40) 1.42 (1.03–1.97) 0.92 (0.11–7.59) NO2 6 months 0.90 (0.16–4.93) 2.15×10−6 (1.39×10−7–3.32×10−5) 1.32 (0.97–1.81) 1.93 (0.98–3.80) 0.58 (0.18–1.92) 2.38×10−6 (2.62×10−7–2.16×10−5) 0.96 (0.41–2.21) 5.09×10−6 (6.23e×10−7–4.16×10−5) 3.05 (0.48–19.48) 1.77×10−5 (4.45×10−7–7.04×10−4) 12 months 2.32×10−6 (7.08×10−7–7.60×10−6) 1.93×10−7 (2.74×10−9–1.35×10−5) 1.07 (0.80–1.43) 0.72 (0.27–1.92) 0.58 (0.21–1.62) 1.93×10−7 (2.74×10−9 – 1.35×10−5) 15.89 (3.35–75.46) Benzene 6 months 0.78 (0.52–1.17) 0.78 (0.33–1.83) 1.01 (0.87–1.17) 0.88 (0.64–1.22) 0.96 (0.77–1.19) 1.68 (1.10–2.57) 0.95 (0.48–1.20) 1.00 (0.72–1.39) 0.65 (0.30–1.42) 0.38 (0.13–1.09) 12 months 0.81 (0.36–1.82) 1.37 (0.20–9.59) 1.01 (0.89–1.15) 1.17 (0.90–1.51) 0.83 (0.65–1.05) 0.90 (0.55–1.46) 0.89 (0.74–0.09) 0.92 (0.66–1.28) 2.06 (0.44–9.74) CO 6 months 1.17 (0.74–1.87) 1.53 (0.78–2.98) 1.03 (0.88–1.21) 1.28 (0.99–1.66) 1.03 (0.80–1.33) 0.99 (0.63–1.54) 1.04 (0.85–1.27) 1.19 (0.88–1.60) 1.15 (0.48–2.75) 2.15 (0.90–5.12) 12 months 0.68 (0.22–2.12) 0.56 (0.08–3.97) 1.05 (0.91–1.22) 1.13 (0.89–1.44) 1.01 (0.76–1.34) 0.91 (0.58–1.43) 0.98 (0.79–1.22) 1.01 (0.75–1.35) 1.60 (0.38–6.72) Smoking 6 months 1.28 (0.87–1.88) 0.90 (0.44–1.83) 1.14 (1.00–1.30) 1.12 (0.86–1.47) 0.93 (0.75–1.15) 0.92 (0.62–1.37) 1.01 (0.84–1.22) 1.15 (0.81–1.62) 0.88 (0.46–1.70) 0.93 (0.34–2.62) 12 months 0.79 (0.42–1.50) 0.81 (0.18–3.58) 1 (0.87–1.15) 0.93 (0.74–1.18) 1.21 (0.96–1.53) 1.43 (0.95–2.17) 1.03 (0.87–1.21) 1.05 (0.77–1.41) 6.77 (0.91–50.53) Toluene 6 months 0.55 (0.24–1.27) 0.86 (0.23–3.17) 0.95 (0.74–1.22) 1.23 (0.82–1.83) 0.88 (0.61–1.27) 0.52 (0.25–1.09) 0.99 (0.73–1.35) 5.57×10−7 (3.22×10−7–9.64×10−7) 12 months 0.82 (0.22–3.04) 1.00×10−7 (1.95×10−7–5.16×10−7) 1.1 (0.90–1.34) 1.00 (0.70–1.43) 1.15 (0.83–1.59) 1.14 (0.62–2.11) 1.13 (0.85–1.51) 5.84×10−7 (2.08×10−7–1.64×10−6) Data are presented as risk ratio (95% CI). Adj: adjusted for all the clinical-demographic variables; Adj2: adjusted for all the clinical-demographic variables, plus adjusting for other indoor air pollutants. Risk ratios in bold are statistically significant at p-values derived using Benjamini–Hochberg (p<0.05). Empty cells indicate that model convergence was not achieved. PM10: particulate matter <10 μm in diameter; NO2: nitrogen dioxide; CO: carbon monoxide.
Supplementary Material
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Supplementary tables 00052-2018_supp_tables
Vol 5 Issue 1
Table of Contents
Indoor air pollution and tobacco smoke exposure: impact on nasopharyngeal bacterial carriage in mothers and infants in an African birth cohort study
