Supplemental Material, A longitudinal study of road traffic noise … · 2020. 3. 26. ·...

Supplemental Material, A longitudinal study of road traffic noise and

body mass index trajectories from birth to 8 years

Kjell Vegard Weyde 1,4*, Norun Hjertager Krog 1, Bente Oftedal 1, Per Magnus 2,4, Richard White 3, Stephen Stansfeld 5, Simon Øverland 6, Gunn Marit Aasvang 1,* 1 Department of Air Pollution and Noise, Norwegian Institute of Public Health, Oslo, Norway 2 Centre for Fertility and Health, Norwegian Institute of Public Health, Oslo, Norway 3 Dpartment of Infectious Diseases Epidemiology and Modelling, Norwegian Institute of Public Health, Oslo, Norway 4 Institute of Health and Society, Faculty of Medicine, University of Oslo, Oslo, Norway 5 fCentre for Psychiatry, Wolfson Institute of Preventive Medicine, Barts and the London School of Medicine, Queen Mary University of London, London, United Kingdom 6 Division of Mental Health, Norwegian Institute of Public Health, Bergen, Norway

Contents eTable 1: Participants at each of the time points ............................................................................ 3

eTable 2: Missing (%) for different covariates at different times. ................................................... 4

eTable 3: Comparison of children who dropped out of MoBa, with children in the study sample,. 5

at the different time points ............................................................................................................. 5

eTable 4: Predicted marginal means of BMI for different noise levels during pregnancy,

pregnancy sample (95% confidence interval). ................................................................................. 6

eTable 5: Predicted marginal means of BMI for different noise levels over time (between-persons

noise), childhood sample (95% confidence interval). ...................................................................... 7

eTable 6: Marginal effects of road traffic noise over time (within-person noise, childhood

sample,, per 1 dB increase in Lden), with 95 % confidence intervals. ............................................... 8

eTable 7: Predicted marginal means of BMI for different pregnancy noise levels over time, with

95 % confidence intervals. ............................................................................................................... 9

eTable 8: Predicted marginal means of BMI for different childhood noise levels over time, with 95

% confidence intervals. Results of sensitivity analyses with rail traffic noise, air pollution and diet.

....................................................................................................................................................... 10

eTable 9: Marginal effects of road traffic noise over time (noise within; childhood sample only,

per 1 dB increase in Lden), with 95 % confidence intervals. Results of sensitivity analyses with rail

traffic noise, air pollution and diet. ............................................................................................... 11

eTable 10: Coefficients from linear regression analyses for road traffic noise, with 95%

confidence intervals ....................................................................................................................... 12

eTable 11: Predicted BMI for different pregnancy noise categories, original sample, complete

cases and imputed ......................................................................................................................... 13

eTable 12: Predicted BMI for different childhood noise categories, original sample, complete

cases and imputed ......................................................................................................................... 14

eFigure 1: Directed Aclyclic Graphs (DAGs), childhood sample ..................................................... 15

eFigure 2: BMI percentiles for girls (left) and boys (right) from birth to age 8 years (96 months).

....................................................................................................................................................... 16

eAppendix 1 ................................................................................................................................... 17

https://www.fhi.no/en/about/about-niph/departments-and-centres/infectious-diseases/

eAppendix 2 ................................................................................................................................... 17

References ..................................................................................................................................... 19

eTable 1: Participants at each of the time points

Time point

Age

Pregnancy sample. Number of participants (% of initial population)

Childhood sample. Number of participants (% of initial population)

Number of childhood

sample participants moved once

Number of childhood

sample participants moved twice

or more

0 Birth 6776 (58.6) - 1 18 months 4350 (37.6) 4909 (42.5) 865 43 2 3 years 3482 (30.1) 2925 (25.3) 1041 127 3 5 years 3636 (31.5) 3037 (26.3) 1376 360 4 7 years 2989 (25.9) 2352 (20.4) 1056 363 5 8 years 1742 (15.1) 1362 (11.8) 521 165

eTable 2: Missing (%) for different covariates at different times. Time

Time varying 0 1 2 3 4 5 Total Time constant

BMI 42 55 54 61 78 48.4 Gender 0 Road traffic noisea 45 64 69 75 84 56 Education 1 Age 0 31 44 49 56 72 42.1 Ethnicity 0.3 Incomeb 4 2 1 8 26 7 Maternal BMI 10 Urbanityc 44 63 68 75 84 56 BMI at birth 4 Pregnancy noise 31 Income, birth 4 Urbanity, birth 14

aLden, at most exposed facade. bGross household income, adjusted according to the consumer price index. cIndicates proximity to city center; center, outskirts, or between.

eTable 3: Comparison of children who dropped out of MoBa, with children in the study sample,

at the different time points Variable Time Non-

participants Pregnancy

sample p-value Non-

participants Childhood

sample p-value:

Gender, % male 0 50.3 51.0 .45 1 51.1 49.9 .19 51.1 50.0 .21 2 50.7 50.6 .87 50.8 50.2 .57 3 50.9 50.1 .45 50.8 50.4 .71 4 51.0 49.8 .27 50.8 50.1 .56 5 50.8 50.0 .55 50.8 49.7 .45

Urbanitya, % Center

0

27.5

26.5

.07

Center 1 29.0 24.0 <.001 27.8 18.9 <.001 Center 2 27.7 25.3 .03 15.9 15.1 .11 Center 3 27.4 26.0 .12 12.3 10.5 .28 Center 4 27.6 25.1 .02 7.2 8.4 .37 Center 5 27.7 22.7 <.001 7.0 7.5 .81

Education, % Max high school

0

21.2

16.3

<.001

Max high school 1 20.6 14.6 <.001 21.3 14.3 <.001 Max high school 2 20.8 12.7 <.001 20.4 12.3 <.001 Max high school 3 20.8 12.9 <.001 20.2 13.3 <.001 Max high school 4 20.2 13.2 <.001 19.7 13.3 <.001 Max high school 5 19.4 12.7 <.001 19.2 12.4 <.001

Ethnicityb, % nonwestern 0 15.4 9.8 <.001 1 14.5 8.2 <.001 14.7 8.7 <.001 2 14.3 7.1 <.001 13.4 8.6 <.001 3 14.2 7.8 <.001 13.0 9.9 <.001 4 13.7 7.8 <.001 12.8 10.1 <.001 5 13.1 7.3 <.001 12.7 8.9 <.001

BMI 0 13.8 14.0 <.0001 1 16.7 16.7 .05 16.7 16.7 .50 2 16.1 16.1 .28 16.1 16.1 1.00 3 15.4 15.4 .84 15.4 15.4 .78 4 15.6 15.5 .33 15.6 15.6 .89 5 16.0 15.9 .60 16.0 15.9 .12

Birth BMI 0 1 13.9 14.0 .05 2 13.9 14.0 <.001 3 13.9 14.0 <.001 4 13.9 14.1 <.001 5 13.9 14.1 <.001

Road traffic noise,Lden, dB 0 56.7 56.4 .16 1 56.9 56.0 <.0001 56.4 55.4 <.0001 2 56.6 56.2 .08 54.6 54.8 .34 3 56.6 56.3 .10 54.4 54.1 .30 4 56.7 55.9 <.0001 53.4 53.5 .84 5 56.6 55.7 .0001 54.1 53.3 .04

Incomec 0 738523 793541 <.0001 1 759197 789665 .007 760882 783868 .04 2 773031 819518 .001 775853 819596 .003 3 857241 900098 .001 852379 922698 <.001 4 928825 955106 .08 919357 997773 <.001 5 955503 992816 .04 952134 1022064 <.001

BMI_mother 0 22.8 23.0 .004 1 22.9 23.0 .16 22.9 22.9 .54 2 22.9 22.9 .47 22.9 22.9 .54 3 22.9 22.9 .76 22.9 22.9 .58 4 22.9 22.9 .91 22.9 22.8 .23 5 22.9 23.0 .53 22.9 22.8 .40

aOutskirts: outside the Ring 3 road; Between: between roads Ring 2 and Ring 3; Center: inside Ring 2 road. The covariate indicated how far the children lived from the city center. bDichotomized according to Statistics Norway1. cAdjusted according to consumer price index

eTable 4: Predicted marginal means of BMI for different noise levels during pregnancy, pregnancy

sample (95% confidence interval). Analysis Predicted BMI

Birth

Predicted BMI

18 months

Predicted BMI

3 years

Predicted BMI

5 years

Predicted BMI

7 years

Predicted BMI

8 years

Main modela:

Average noise level

Lden 45 dB 14.05 (14.00,

14.10)

16.88 (16.82, 16.94) 16.14 (16.07, 16.21) 15.41 (15.34, 15.49) 15.45 (15.36, 15.54) 15.83 (15.73, 15.94)

Lden 50 dB 14.02 (13.99,

14.06)

16.89 (16.84, 16.93) 16.14 (16.09, 16.19) 15.43 (15.37, 15.48) 15.48 (15.41, 15.54) 15.87 (15.79, 15.94)

Lden 55 dB 14.00 (13.97,

14.03)

16.89 (16.86, 16.93) 16.14 (16.10, 16.18) 15.44 (15.40, 15.49) 15.50 (15.44, 15.55) 15.90 (15.83, 15.96)

Lden 60 dB 13.97 (13.94,

14.01)

16.90 (16.86, 16.94) 16.14 (16.09, 16.18) 15.46 (15.41, 15.51) 15.52 (15.46, 15.58) 15.93 (15.86, 16.00)

Lden 65 dB 13.95 (13.91,

13.99)

16.91 (16.85, 16.96) 16.14 (16.07, 16.20) 15.47 (15.41, 15.54) 15.55 (15.47, 15.63) 15.96 (15.86, 16.05)

aMain model includes age, gender, household income, urbanity, mother’s education, ethnicity, and mother’s BMI at birth.

eTable 5: Predicted marginal means of BMI for different noise levels over time (between-persons

noise), childhood sample (95% confidence interval).

Analysis Predicted BMI

18 months

Predicted BMI

3 years

Predicted BMI

5 years

Predicted BMI

7 years

Predicted BMI

8 years

Main modela:

Average noise level

Lden average 45 dB 16.66 (16.60, 16.71) 16.12 (16.04, 16.19) 15.44 (15.36, 15.52) 15.49 (15.40, 15.59) 15.88 (15.77, 15.99)

Lden average 50 dB 16.66 (16.62, 16.70) 16.11 (16.06, 16.16) 15.45 (15.39, 15.51) 15.51 (15.45, 15.58) 15.91 (15.83, 15.99)

Lden average 55 dB 16.66 (16.63, 16.70) 16.10 (16.05, 16.14) 15.45 (15.41, 15.50) 15.53 (15.48, 15.59) 15.94 (15.87, 16.01)

Lden average 60 dB 16.67 (16.62, 16.71) 16.09 (16.03, 16.14) 15.46 (15.40, 15.52) 15.56 (15.48, 15.63) 15.97 (15.88, 16.06)

Lden average 65 dB 16.67 (16.61, 16.72) 16.07 (16.00, 16.15) 15.46 (15.38, 15.55) 15.58 (15.47, 15.68) 16.00 (15.88, 16.13)

aMain model includes age, gender, household income, urbanity, mother’s education, ethnicity, and mother’s BMI at birth, child’s BMI at birth.

eTable 6: Marginal effects of road traffic noise over time (within-person noise, childhood sample,, per 1

dB increase in Lden), with 95 % confidence intervals. Analysis Predicted change in BMI

per 1 dB increase in Lden

18months

Predicted change in BMI


3years



5years



7years



8years

Maina -.0021 (-.0098, .0056) -.0100 (-.0235, .0036) .0084 (-.0062, .0231) .0008 (-.0146, .0163) .0040 (-.0138, .0218)

aMain model includes age, gender, household income, urbanity, mother’s education, ethnicity, and mother’s BMI at birth, child’s BMI at birth.

eTable 7: Predicted marginal means of BMI for different pregnancy noise levels over time, with 95 %

confidence intervals. Pregnancy exposure

Analysis Birth 18 m 3 y 5 y 7 y 8 y

Maina with rail traffic noiseb:

average 50 dB 14.02 (13.99,14.06) 16.89 (16.84,16.93) 16.14 (16.09,16.19) 15.43 (15.37,15.48) 15.47 (15.41,15.54) 15.86 (15.79,15.94) average 55 dB 14.00 (13.97, 14.03) 16.89 (16.86, 16.93) 16.14 (16.10, 16.18) 15.44 (15.40, 15.49) 15.50 (15.44, 15.55) 15.90 (15.83, 15.96) average 60 dB 13.98 (13.94, 14.01) 16.90 (16.86, 16.94) 16.14 (16.09, 16.18) 15.46 (15.41, 15.51) 15.52 (15.46, 15.58) 15.93 (15.86, 16.00) average 65 dB 13.95 (13.91, 13.99) 16.91 (16.86, 16.96) 16.14 (16.08, 16.20) 15.47 (15.41, 15.54) 15.55 (15.47, 15.63) 15.96 (15.87, 16.05) Excl pregn air

pollution:

50 dB 14.02 (13.99, 14.06) 16.88 (16.84, 16.93) 16.14 (16.08, 16.19) 15.43 (15.37, 15.48) 15.48 (15.41, 15.54) 15.87 (15.79, 15.94) 55 dB 14.00 (13.97, 14.03) 16.89 (16.86, 16.93) 16.14 (16.09, 16.18) 15.44 (15.40, 15.49) 15.50 (15.44, 15.55) 15.90 (15.83, 15.96) 60 dB 13.98 (13.94, 14.01) 16.90 (16.86, 16.94) 16.14 (16.09, 16.18) 15.46 (15.41, 15.51) 15.52 (15.46, 15.58) 15.93 (15.86, 16.00) 65 dB 13.95 (13.91, 13.99) 16.91 (16.86, 16.96) 16.14 (16.08, 16.209 15.47 (15.41, 15.54) 15.54 (15.47, 15.63) 15.96 (15.86, 16.05)

Incl pregn NO2: 50 dB 14.02 (13.98, 14.06) 16.88 (16.83, 16.92) 16.13 (16.08, 16.18) 15.42 (15.36, 15.48) 15.47 (15.40, 15.54) 15.86 (15.78, 15.94) 55 dB 14.00 (13.97, 14.03) 16.89 (16.85, 16.93) 16.14 (16.09, 16.18) 15.44 (15.40, 15.49) 15.50 (15.44, 15.55) 15.89 (15.83, 15.96)

60 dB 13.98 (13.95, 14.01) 16.90 (16.86, 16.94) 16.14 (16.09, 16.19) 15.46 (15.41, 15.51) 15.53 (15.47, 15.59) 15.93 (15.86, 16.00) 65 dB 13.96 (13.91, 14.00) 16.92 (16.86, 16.97) 16.14 (16.08, 16.21) 15.48 (15.41, 15.55) 15.55 (15.47, 15.64) 15.96 (15.87, 16.06)

Incl pregn NOX 50 dB 14.02 (13.98, 14.06) 16.88 (16.84, 16.93) 16.13 (16.08, 16.19) 15.42 (15.37, 15.48) 15.47 (15.41, 15.54) 15.86 (15.78, 15.94) 55 dB 14.00 (13.97, 14.03) 16.89 (16.86, 16.93) 16.14 (16.09, 16.18) 15.44 (15.40, 15.49) 15.50 (15.44, 15.55) 15.90 (15.83, 15.96) 60 dB 13.98 (13.95, 14.01) 16.90 (16.86, 16.94) 16.14 (16.09, 16.18) 15.46 (15.41, 15.51) 15.53 (15.46, 15.59) 15.93 (15.86, 16.00) 65 dB 13.96 (13.91, 14.00) 16.91 (16.86, 16.97) 16.14 (16.08, 16.20) 15.48 (15.41, 15.54) 15.55 (15.47, 15.63) 15.96 (15.87, 16.06)

Incl preg PM2.5 50 dB 14.02 (13.99, 14.06) 16.88 (16.84, 16.93) 16.13 (16.08, 16.19) 15.42 (15.37, 15.48) 15.48 (15.41, 15.54) 15.86 (15.79, 15.94) 55 dB 14.00 (13.97, 14.03) 16.89 (16.86, 16.93) 16.14 (16.09, 16.18) 15.44 (15.40, 15.49) 15.50 (15.45, 15.55) 15.90 (15.83, 15.96) 60 dB 13.98 (13.94, 14.01) 16.90 (16.86, 16.94) 16.14 (16.09, 16.18) 15.46 (15.41, 15.51) 15.52 (15.46, 15.58) 15.93 (15.86, 16.00) 65 dB 13.95 (13.91, 14.00) 16.91 (16.86, 16.96) 16.14 (16.08, 16.20) 15.48 (15.41, 15.54) 15.55 (15.47, 15.63) 15.96 (15.86, 16.05)

aMain model includes age, gender, household income, urbanity, mother’s education, ethnicity, and mother’s BMI at birth. bLden

eTable 8: Predicted marginal means of BMI for different childhood noise levels over time, with 95 %

confidence intervals. Results of sensitivity analyses with rail traffic noise, air pollution and diet. Childhood Exposure

Analysis 18 m 3 y 5 y 7 y 8 y

Maina with rail traffic noiseb:

average 50 dB 16.66 (16.62, 16.70) 16.11 (16.06, 16.16) 15.45 (15.39, 15.51) 15.52 (15.45, 15.58) 15.91 (15.83, 15.99) average 55 dB 16.66 (16.63, 16.70) 16.10 (16.05, 16.14) 15.45 (15.41, 15.50) 15.53 (15.48, 15.59) 15.94 (15.87, 16.01) average 60 dB 16.66 (16.62, 16.70) 16.08 (16.03, 16.14) 15.46 (15.40, 15.52) 15.55 (15.48, 15.63) 15.97 (15.88, 16.06) average 65 dB 16.66 (16.61, 16.72) 16.07 (15.99, 16.15) 15.46 (15.37, 15.55) 15.57 (15.47, 15.68) 16.00 (15.87, 16.13) Excl pregn air

pollution:

50 dB 16.66 (16.62, 16.70) 16.11 (16.06, 16.17) 15.45 (15.39, 15.50) 15.54 (15.47, 15.61) 15.93 (15.85, 16.01) 55 dB 16.66 (16.63, 16.70) 16.10 (16.06, 16.15) 15.45 (15.40, 15.50) 15.55 (15.49, 15.61) 15.96 (15.89, 16.03) 60 dB 16.66 (16.62, 16.70) 16.09 (16.03, 16.15) 15.46 (15.40, 15.52) 15.56 (15.48, 15.64) 15.99 (15.90, 16.08) 65 dB 16.66 (16.60, 16.72) 16.08 (16.00, 16.16) 15.47 (15.38, 15.56) 15.57 (15.46, 15.68) 16.02 (15.89, 16.15)

Incl pregn NO2: 50 dB 16.66 (16.62, 16.71) 16.11 (16.06, 16.17) 15.45 (15.39, 15.50) 15.54 (15.47, 15.61) 15.93 (15.84, 16.01) 55 dB 16.66 (16.63, 16.70) 16.10 (16.06, 16.15) 15.45 (15.40, 15.50) 15.55 (15.49, 15.61) 15.96 (15.89, 16.03)

60 dB 16.66 (16.62, 16.70) 16.09 (16.03, 16.15) 15.46 (15.40, 15.52) 15.56 (15.48, 15.64) 15.99 (15.90, 16.09)

65 dB 16.66 (16.60, 16.72) 16.08 (16.00, 16.16) 15.47 (15.38, 15.56) 15.57 (15.46, 15.68) 16.02 (15.89, 16.15) Incl pregn NOX

50 dB 16.66 (16.62, 16.70) 16.11 (16.06, 16.17) 15.45 (15.39, 15.50) 15.54 (15.47, 15.61) 15.93 (15.84, 16.01) 55 dB 16.66 (16.63, 16.70) 16.10 (16.06, 16.15) 15.45 (15.40, 15.50) 15.55 (15.49, 15.61) 15.96 (15.89, 16.03) 60 dB 16.66 (16.62, 16.71) 16.09 (16.03, 16.15) 15.46 (15.40, 15.52) 15.56 (15.48, 15.64) 15.99 (15.90, 16.08) 65 dB 16.66 (16.60, 16.72) 16.08 (16.00, 16.16) 15.47 (15.38, 15.56) 15.57 (15.46, 15.68) 16.02 (15.89, 16.15)

Incl preg PM2.5 50 dB 16.67 (16.63, 16.71) 16.12 (16.06, 16.17) 15.45 (15.39, 15.51) 15.54 (15.47, 15.61) 15.93 (15.85, 16.01) 55 dB 16.66 (16.63, 16.70) 16.10 (16.06, 16.15) 15.45 (15.40, 15.50) 15.55 (15.49, 15.61) 15.96 (15.89, 16.03) 60 dB 16.66 (16.62, 16.70) 16.09 (16.03, 16.14) 15.46 (15.40, 15.52) 15.56 (15.48, 15.64) 15.99 (15.89, 16.08) 65 dB 16.66 (16.60, 16.72) 16.07 (15.99, 16.15) 15.46 (15.37, 15.55) 15.57 (15.46, 15.68) 16.02 (15.89, 16.15)

Without child air pollution

50 dB 16.67 (16.63, 16.71) 16.12 (16.06, 16.17) 15.48 (15.41, 15.54) 15.52 (15.43, 15.60) 15.98 (15.85, 16.11) 55 dB 16.67 (16.63, 16.70) 16.10 (16.06, 16.15) 15.47 (15.41, 15.52) 15.55 (15.47, 15.63) 16.01 (15.90, 16.12) 60 dB 16.67 (16.62, 16.71) 16.09 (16.03, 16.14) 15.46 (15.39, 15.53) 15.58 (15.48, 15.68) 16.04 (15.89, 16.18) 65 dB 16.66 (16.61, 16.72) 16.07 (15.99, 16.15) 15.45 (15.35, 15.55) 15.62 (15.48, 15.75) 16.06 (15.86, 16.27)

Incl childh NO2 50 dB 16.66 (16.62, 16.70) 16.11 (16.06, 16.17) 15.47 (15.41, 15.54) 15.52 (15.43, 15.60) 15.98 (15.85, 16.11) 55 dB 16.67 (16.63, 16.70) 16.10 (16.06, 16.15) 15.47 (15.41, 15.53) 15.55 (15.48, 15.63) 16.01 (15.90, 16.12) 60 dB 16.67 (16.63, 16.71) 16.09 (16.03, 16.15) 15.47 (15.39, 15.54) 15.59 (15.49, 15.69) 16.04 (15.89, 16.19) 65 dB 16.67 (16.61, 16.73) 16.08 (16.00, 16.16) 15.46 (15.36, 15.56) 15.62 (15.49, 15.76) 16.07 (15.87, 16.28)

Incl childh NOX 50 dB 16.66 (16.62, 16.70) 16.11 (16.06, 16.17) 15.47 (15.41, 15.54) 15.51 (15.43, 15.60) 15.98 (15.85, 16.10) 55 dB 16.67 (16.63, 16.70) 16.10 (16.06, 16.15) 15.47 (15.41, 15.53) 15.55 (15.48, 15.63) 16.01 (15.90, 16.12) 60 dB 16.67 (16.63, 16.71) 16.09 (16.04, 16.15) 15.47 (15.40, 15.54) 15.59 (15.49, 15.69) 16.05 (15.90, 16.19) 65 dB 16.68 (16.63, 16.74) 16.08 (16.00, 16.16) 15.47 (15.37, 15.57) 15.63 (15.49, 15.77) 16.08 (15.87, 16.29)

Incl child PM2.5 50 dB 16.67 (16.63, 16.71) 16.12 (16.06, 16.17) 15.48 (15.41, 15.54) 15.52 (15.43, 15.60) 15.98 (15.85, 16.11) 55 dB 16.67 (16.63, 16.70) 16.10 (16.06, 16.15) 15.47 (15.41, 15.52) 15.55 (15.47, 15.63) 16.01 (15.89, 16.12) 60 dB 16.67 (16.62, 16.71) 16.09 (16.03, 16.14) 15.46 (15.39, 15.53) 15.58 (15.48, 15.68) 16.04 (15.89, 16.18)

65 dB 16.67 (16.61, 16.73) 16.07 (15.99, 16.15) 15.45 (15.35, 15.55) 15.62 (15.48, 15.75) 16.06 (15.86, 16.27) Without diet at

3 y

50 dB 16.68 (16.63, 16.72) 16.12 (16.06, 16.18) 15.46 (15.40, 15.53) 15.51 (15.44, 15.59) 15.91 (15.82, 16.00) 55 dB 16.68 (16.64, 16.72) 16.11 (16.06, 16.16) 15.48 (15.42, 15.53) 15.52 (15.45, 15.59) 15.92 (15.84, 16.00) 60 dB 16.68 (16.64, 16.73) 16.10 (16.04, 16.16) 15.49 (15.42, 15.56) 15.52 (15.44, 15.61) 15.93 (15.83, 16.04) 65 dB 16.69 (16.62, 16.75) 16.08 (16.00, 16.17) 15.50 (15.40, 15.60) 15.53 (15.41, 15.65) 15.94 (15.79, 16.09)

Incl diet at 3 y 50 dB 16.68 (16.63, 16.72) 16.12 (16.06, 16.18) 15.47 (15.40, 15.53) 15.52 (15.44, 15.59) 15.91 (15.82, 16.00) 55 dB 16.68 (16.64, 16.72) 16.11 (16.06, 16.16) 15.48 (15.42, 15.53) 15.52 (15.45, 15.59) 15.92 (15.84, 16.00) 60 dB 16.68 (16.64, 16.73) 16.10 (16.04, 16.16) 15.49 (15.42, 15.56) 15.52 (15.44, 15.61) 15.93 (15.83, 16.04) 65 dB 16.69 (16.62, 16.75) 16.08 (16.00, 16.17) 15.50 (15.40, 15.60) 15.53 (15.41, 15.65) 15.94 (15.79, 16.09)

aMain model includes age, gender, household income, urbanity, mother’s education, ethnicity, and mother’s BMI at birth, child’s BMI at birth. bLden

eTable 9: Marginal effects of road traffic noise over time (noise within; childhood sample only, per 1 dB

increase in Lden), with 95 % confidence intervals. Results of sensitivity analyses with rail traffic noise, air

pollution and diet. Analysis N 18 m 3 y 5 y 7 y 8 y

Maina 6403 (14585) -.0021 (-.0098, .0056) -.0100 (-.0235, .0036) .0084 (-.0062, .0231) .0008 (-.0146, .0163) .0040 (-.0138, .0218) Including rail traffic noiseb 6403 (14585) -.0019 (-.0096, .0059) -.0083 (-.0217, .0052) .0084 (-.0061, .0229) -.0001 (-.0155, .0152) .0036 (-.0140, .0212)

Excl pregn air poll 6225 (14275) -.0034 (-.0112, .0044) -.0095 (-.0234, .0044) .0102 (-.0047, .0252) .0019 (-.0141, .0180) .0031 (-.0149, .0212) Including pregnancy NO2 6225 (14275) -.0034 (-.0113, .0045) -.0095 (-.0234, .0044) .0103 (-.0047, .0253) .0020 (-.0141, .0180) .0032 (-.0148, .0212) Including pregnancy NOX 6225 (14275) -.0033 (-.0112, .0045) -.0095 (-.0234, .0044) .0102 (-.0048, .0252) .0019 (-.0141, .0180) .0031 (-.0149, .0212) Including pregnancyPM2.5 6225 (14275) -.0039 (-.0118, .0040) -.0095 (-.0234, .0044) .0108 (-.0041, .0258) .0024 (-.0136, .0185) .0035 (-.0145, .0216)

Excl childhood air poll 6180 (11861) -.0020 (-.0099, .0059) -.0094 (-.0232, .0044) .0106 (-.0080, .0291) -.0071 (-.0300, .0157) -.0015 (-.0343, .0314) Including childhood NO2 6180 (11861) -.0024 (-.0103, .0056) -.0096 (-.0233, .0042) .0098 (-.0087, .0284) -.0082 (-.0312, .0147) -.0024 (-.0353, .0305) Including childhood NOX 6180 (11861) -.0028 (-.0108, .0051) -.0094 (-.0232, .0043) .0094 (-.0092, .0279) -.0088 (-.0318, .0141) -.0030 (-.0359, .0299)

Including childhood PM2.5 6180 (11861) -.0019 (-.0098, .0060) -.0094 (-.0231, .0044) .0108 (-.0077, .0293) -.0066 (-.0295, .0164) -.0011 (-.0340, .0318) Excluding dietc at age 3 y 4555 (11498) .0007 (-.0079, .0093) -.0081 (-.0219, .0057) .0114 (-.0045, .0272) -.0007 (-.0173, .0159) .0036 (-.0162, .0235) Including diet at age 3 y 4555 (11498) .0009 (-.0077, .0095) -.0097 (-.0236, .0043) .0115 (-.0045, .0275) .0004 (-.0163, .0171) .0045 (-.0156, .0247)

aMain model includes age, gender, household income, urbanity, mother’s education, ethnicity, and mother’s BMI at birth, child’s BMI at birth. bLden

cBased on the New Nordic Diet 2, and contained information on intake of fruits, potatoes, rice, pasta, vegetables, bread, fish, milk, juice, water, sweetened beverages and sweet and salty snacks.

eTable 10: Coefficients from linear regression analyses for road traffic noise, with 95% confidence

intervals Analysisa N Beta coefficient, road

traffic noise

Without dietb 2062 .0037 (-.0053, .0126)

Incl diet 2062 .0038 (-.0051, .0128)

Without physical activityc 2317 .0081 (-.0005, .0167)

Incl physical activity 2317 .0079 (-.0007, .0165)

aAll analyses are with both covariates and outcomes at age 7 years. bBased on the New Nordic Diet 2, and contained information on intake of fruits, potatoes, rice, pasta, vegetables, bread, fish, milk, juice, water, sweetened

beverages and sweet and salty snacks. cHours a week the child was physically active/doing sports (football, handball, skiing, etc.) when not in school, with six alternatives: less than one hour, 1-2

hours, 3-4 hours, 5-7 hours 8-10 hours, or more than 11 hours

eTable 11: Predicted BMI for different pregnancy noise categories, original sample, complete cases and

imputed <55 dB 55-60 dB >=60 dB

Time Original, mean (SD), obs

Complete, mean (SD), obs=366

Imputeda, mean (SD), obs=2759

Original, mean (SD), obs






0 14.04 (.19) obs=2671

14.07 (.19) 14.04 (.20) 13.99 (.19) obs=1888

14.01 (.18) 13.99 (.19) 13.94 (.19) obs=2217

13.96 (.18) 13.94 (.19)

1 16.74 (.31) obs=1784

16.73 (.33) 16.73 (.31) 16.75 (.30) obs=1221

16.74 (.32) 16.74 (.31) 16.75 (.30) obs=1345

16.78 (.33) 16.75 (.30)

2 16.11 (.22) obs=1408

16.06 (.23) 16.10 (.22) 16.09 (.22) obs=977

16.04 (.22) 16.09 (.22) 16.08 (.21) obs=1097

16.04 (.22) 16.07 (.22)

3 15.42 (.20) obs=1446

15.42 (.19) 15.42 (.20) 15.43 (.19) obs=1022

15.45 (.19) 15.45 (.20) 15.45 (.18) obs=1168

15.49 (.19) 15.46 (.19)

4 15.51 (.19) obs=1238

15.52 (.18) 15.52 (.20) 15.54 (.19) obs=853

15.54 (.18) 15.55 (.19) 15.57 (.18) obs=898

15.55 (.18) 15.58 (.19)

5 15.92 (.19) obs=748

15.94 (.18) 15.92 (.20) 15.97 (.18) obs=481

15.96 (.19) 15.98 (.19) 16.01 (.18) obs=513

15.97 (.18) 16.04 (.19)

All models include age, gender, household income, urbanity, mother’s education, ethnicity, and mother’s BMI at birth. aBased on 50 imputed datasets.

eTable 12: Predicted BMI for different childhood noise categories, original sample, complete cases and

imputed <55 dB 55-60 dB >=60 dB

Time Original, mean (SD), obs









1 16.73 (.34) 2377

16.68 (.43) 16.74 (.40) 16.72 (.35) 1371

16.72 (.47) 16.72 (.39) 16.72 (.35) 1161

16.79 (.50) 16.72 (.41)

2 16.11 (.36) 1463

16.09 (.39) 16.11 (.36) 16.09 (.36) 841

16.00 (.42) 16.07 (.35) 16.04 (.35) 621

15.97 (.45) 16.04 (.37)

3 15.43 (.31) 1555

15.35 (.35) 15.45 (.35) 15.41 (.34) 872

15.41 (.38) 15.44 (.33) 15.45 (.33) 610

15.48 (.39) 15.45 (.35)

4 15.55 (.34) 1283

15.46 (.34) 15.56 (.35) 15.55 (.33) 647

15.50 (.36) 15.56 (.33) 15.59 (.34) 422

15.55 (.37) 15.57 (.35)

5 15.97 (.31) 777

15.87 (.36) 16.00 (.34) 16.00 (.36) 349

15.95 (.37) 16.02 (.33) 16.03 (.32) 236

16.02 (.40) 16.04 (.34)

All models include age, gender, household income, urbanity, mother’s education, ethnicity, and mother’s BMI at birth, child’s BMI at birth. aBased on 50 imputed datasets.

eFigure 1: Directed Aclyclic Graphs (DAGs), childhood sample

B M I p e rc e n t ile s , g ir ls

A g e in m o n th s

BM

I (k

g/m

2)

0 18 36 60 84 96

12

13

14

15

16

17

18

19

B M I p e rc e n t ile s , b o y s

A g e in m o n th s

BM

I (k

g/m

2)

5th

25 th

50 th

75 th

95 th

0 18 36 60 84 96

12

13

14

15

16

17

18

19

eFigure 2: BMI percentiles for girls (left) and boys (right) from birth to age 8 years (96 months).

eAppendix 1

Linear mixed models

For the childhood model, an intra-class correlation for the null model (containing BMI and random

intercept) of .44, in addition to a confidence interval for the random intercept variance not including

zero (CI=[.96, 1.09]), warranted use of the mixed model. The covariates from the final model were

used in a linear regression analysis with a leverage versus squared residuals plot to identify potential

outliers. No outliers were detected. To address the assumption of normally distributed residuals,

histograms were made for level 1 residuals, random intercept and random slope. Scatterplots with

smoothed curves were used to examine whether the covariates were linearly related to the

outcome. The assumption of independent residuals was checked by plotting of the residuals from

each time point against each other in a scatterplot and by obtaining a correlation matrix of the

residuals. The homoscedasticity of variance assumption was evaluated through visual inspection of

scatterplots with standardized residuals against age and against fitted values of the outcome

variable. Several approaches were tried to reduce the heteroscedasticity: inclusion of interaction

terms, allowing for different variances at each time points, log-transforming the BMI variable, or

doing some other transformation, such as square root. The best solution seemed to be keeping the

BMI variable in its original form, still, however, leaving some heteroscedasticity in the model. By

investigating residual plots and comparing Akaike’s information criterion (AIC) and Bayesian

information criterion (BIC), we found that heteroscedasticity was a bigger problem than correlation

within the residuals and thus prioritized that in our model. For a description of diagnostics employed.

eAppendix 2

Multiple imputation

In longitudinal analysis, assessing reasons for missing is important. Data should be missing at

random, which means that the probability of being missing is not allowed to depend on the

responses we would have observed if the data had not been missing, but it is allowed to depend on

covariates or responses at previous occasions 3. Since the average BMI values in the present study

are similar for study samples and non-participants at most time points, there is no reason to believe

that missing depended on the children’s BMI levels.

Assuming information was missing at random, 50 imputed datasets were created, and then analyzed

with Stata’s mi commands. Chained equations were used to perform the multivariate imputation 4. In

the pregnancy sample, BMI and age were imputed. In the childhood sample, BMI, road traffic noise,

age, income, and urbanity were imputed. The variables used in the imputation equations were the

same as in the main models. The analyses with imputed data in the pregnancy sample included

42210 observations from 7035 children. The analyses with imputed data in the childhood sample

included 50305 observations from 10061 children. Wald tests were used to assess significance of

interaction terms. Additional analyses based on original data from children with no missing data

(pregnancy sample: n=815, obs.=4890; childhood sample: n=494, obs.=2560) were also done to

assess the adequacy of the results obtained with imputed data. Average predicted BMI values for

different noise categories (<50 dB, 50-55 dB, 55-60 dB, 60-65 dB, >65 dB) were then obtained and

compared for the models based on the three different data sets (original, complete cases, imputed).

In addition, the adequacy of the imputed data was assessed through plots of the distributions of the

variables in the observed, imputed and completed samples. Bivariate scatterplots with overlaid

lowess fit for observed and imputed raw values and predicted values were created for each imputed

data set.

For both observed and imputed values, scatterplots of predicted values and covariates with overlaid

lowess curves, and Kernel density plots for the different covariates, were created. These plots

indicated that the imputed data were reasonable.

References 1. Høydal E. Innvandrerbegreper i statistikken: Vestlig og ikke-vestlig – ord som ble for store og

gikk ut på dato. Samfunnsspeilet 2008(4):66-69. 2. Hillesund ER, Bere E, Haugen M, Overby NC. Development of a New Nordic Diet score and its

association with gestational weight gain and fetal growth - a study performed in the Norwegian Mother and Child Cohort Study (MoBa). Public Health Nutr 2014;17(9):1909-18.

3. Rabe-Hesketh S, Skrondal A. Multilevel and Longitudinal Modeling Using Stata. Texas: Stata Press, 2012.

4. Azur MJ, Stuart EA, Frangakis C, Leaf PJ. Multiple imputation by chained equations: what is it and how does it work? Int J Methods Psychiatr Res 2011;20(1):40-9.

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