Fetal growth restriction in association with particulate air pollution before and during pregnancy www.milieu-en-gezondheid.be tim.nawrot@uhasselt.be What is the clinical meaning of fetal growth restriction Why should we study it? www.milieu-en-gezondheid.be Circulation 2005;112:1414-1418 www.milieu-en-gezondheid.be Lancet 2005;365:1484-1486 www.milieu-en-gezondheid.be Blood pressure and birth weight Am J Epidemiol 2007;166:413–420 www.milieu-en-gezondheid.be Aims • To study the risk of fetal growth restriction in associaotin with outdoor PM10 concentrations at the mothers’ residence • To study potential effect modification by gestational duration • To assess the shape of the association • To compare the effects on birth weight with biomass exposure (develomental countries), ETS and maternal smoking during pregnancy www.milieu-en-gezondheid.be Methods (1) • SPE data on 345,081 singleton newborns • Interpolation method and population weighted on the level of municipality • Calculation of exposure for each trimester, period (14 days) around conception and 80 days before conception • Polynomial models to study the shape of the association • Systematic comparison with ETS, smoking, biomass www.milieu-en-gezondheid.be Exposure interpolation and weigthing www.milieu-en-gezondheid.be Methods (2) Based on meta-analytic data comparison estimates for biomass, ETS exposure and maternal smoking were plotted against estimated average daily dose of fine particulate matter from these exposures www.milieu-en-gezondheid.be Characteristics Characteristic Mean birth weight (g) Gender Male Female Season Cold Warm SES Low Medium High Parity ≥4 Gestation age (weeks) < 32 32-36 > 36 Maternal age (years) < 20 20-24 25-29 30-34 35-39 3267 3397 3328 3338 3323 3340 3360 3263 3392 3408 3382 1296 2332 3371 3149 3243 3326 3375 3359 www.milieu-en-gezondheid.be Birth weight changes calculated for a 10 µg/m³ increase Period Estimate (95% CI) Conception (14 days) -5.74 -7.27 -4.22 Trimester -12.6 -15.0 -10.3 Trimester -14.2 -16.6 -11.9 Trimester -13.0 -15.5 -10.5 Overal Pregnancy -17.8 -20.6 -15.1 Gestation Estimate (95% CI) 36 36 36 36 36 0.11 -13.1 -5.59 21.2 -38.6 -12.3 16.5 -33.0 -14.1 8.30 -18.7 -13.4 21.4 -17.8 -17.7 -16.2 -23.3 -7.14 -6.49 -54.5 -14.7 -11.4 -49.4 -16.5 -11.1 -33.9 -15.9 -8.7 -20.6 -20.6 16.5 -2.83 -4.04 48.8 -22.8 -10.0 44.5 -16.5 -11.7 27.7 -3.46 -10.9 51.5 -15.1 -15.0 Adjusted for maternal age, infant gender, parity, season, socioeconomic status, gestational age, time trend www.milieu-en-gezondheid.be Odds ratio for small for gestational age calculated for a 10 µg/m³ increase in exposure around conception and during pregancy 1.3 14 d Conception 1.2 3m 6m 9m Pregnancy Odds ratio 1.1 32-36 w 1.0 > 36 w 0.9 36 w 36 w 36 w 0.9