Background
Methods
Study areas, participants, and baseline questionnaire
Follow-up and outcome measures: the Sapporo cohort
Neurobehavioral development | Allergy | Anthropometric measurements/puberty | |
---|---|---|---|
Sapporo cohort | |||
6–7 months | BSID-II, FTII, EES | ||
1.5 years | BSID-II, DDST, EES | ISAAC | Health checkup data |
3.5 years | K-ABC, CBCL, WAIS-R, EES | ISAAC | Health checkup data |
7 years | WISC-III, WCST-KFS, CBCL, J-PSAI, 2D/4D | ISAAC | Health checkup data |
12 years | Tanner staging, onset of puberty | ||
Hokkaido cohort | |||
1 year | ISAAC, ATS-DLD | Health checkup data | |
1.5 years | M-CHAT | ||
2 years | ISAAC | Health checkup data | |
3 years | KIDS, SDQ | ||
4 years | ISAAC | Health checkup data | |
5 years | SDQ, DCDQ | ||
6 years | ADHD-RS, ASQ | ||
7 years | ISAAC, home visit | Health checkup data | |
8 years | ADHD-RS, Conners 3P, ASQ, CBCL, J-PSAI, WISC-IV | ||
9 years | Tanner staging, onset of puberty |
Follow-up and outcome measures: the Hokkaido cohort
Specimen collection and measurements
Measurement | Method | Specimen |
---|---|---|
Exposure measurements | ||
Dioxins, PCBs, OH-PCBs (congener level) | HRGC/HRMS | Maternal blood, milk |
PFOS, PFOA, and other PFASs | UPLC-MS/MS | Maternal blood |
Phthalate metabolites | GC-MS, LC-MS/MS | Maternal blood, child urine |
Chlorinated pesticides | GC-NCIMS, GC-HRMS | Maternal blood |
Cotinine | ELISA | Maternal and cord blood |
Bisphenol A | ID-LC-MS/MS | Maternal and cord blood |
Me-Hg | Oxygen combustion-gold amalgamation method | Maternal hair |
Phthalate esters and organophosphate flame retardants | GC-MS | House dust |
Mite allergens | ELISA | House dust |
Biological measurements | ||
Thyroid hormones (TSH, FT3, FT) | ELISA | Maternal and cord blood |
Folic acid | CLEIA | Maternal blood |
Fatty acids (palmitic, stearic, palmitoleic, oleic, linoleic, arachidonic, α-linolenic, EPA, DHA) | GC-MS | Maternal blood |
TG | TC E-Test Wako | Maternal blood |
IgE, IgA | ELISA | Cord blood |
Adipokines (adiponectin, leptin) | ELISA and RIA | Cord blood |
Steroid hormones (estradiol, testosterone, progesterone, cortisol, cortisone, DHEA, androstenedione) | LC-MS/MS | Cord blood |
Reproductive hormones (inhibin B, INSL-3, SHBG, FSH, LH) | ELISA, RIA, EIA | Cord blood |
Genetic and epigenetic analysis
Results
Participant characteristics and birth outcomes
Number | Mean (±SD), Med (25–75%), or % | |
---|---|---|
Maternal characteristics | ||
Age at entry (years) | 510 | 30.4 ± 4.9 |
Maternal body mass index | 506 | 21.2 ± 3.2 |
Nulliparous (%) | 240 | 47.7 |
Education (years) | ||
≤9 | 14 | 2.8 |
10–12 | 211 | 41.5 |
13–16 | 274 | 53.9 |
≥17 | 9 | 1.8 |
Household income (million yen/year) | ||
<3 | 95 | 18.8 |
3 to <5 | 250 | 49.5 |
5 to <7 | 105 | 20.8 |
7 to 10 | 48 | 9.5 |
≥10 | 7 | 1.4 |
Drinking habit during pregnancy (%) | 157 | 30.9 |
Smoking habit during pregnancy (%) | 103 | 20.3 |
Caffeine intake during pregnancy (mg/day) | 508 | 124 (76–188) |
Paternal characteristics | ||
Age at entry (years) | 503 | 32.3 ± 5.6 |
Education (years) | ||
≤9 | 31 | 6.1 |
10–12 | 190 | 37.5 |
13–16 | 242 | 47.8 |
≥17 | 43 | 8.5 |
Smoking habit during pregnancy (%) | 354 | 69.8 |
Child characteristics | ||
Sex, boys (%) | 246 | 48.1 |
Gestational age (weeks) | 504 | 38.9 ± 1.5 |
Birth weight (g) | 511 | 3025.6 ± 420.7 |
Birth length (cm) | 511 | 47.9 ± 2.2 |
Types of delivery, vaginal (%) | 397 | 78.8 |
Follow-ups (n = 19,579) | Lost to follow-up (n = 1226) | Sub-cohort (n = 4869) | |||||||
---|---|---|---|---|---|---|---|---|---|
n
| Mean or % | 95% CI |
n
| Mean or % | 95% CI |
n
| Mean or % | 95% CI | |
Maternal characteristics | |||||||||
Age at entry (years) | 19,549 | 29.9 | 29.8–29.9 | 1166 | 29.4 | 29.1–29.7 | 4831 | 29.9 | 29.8–30.0 |
Maternal body mass index | 18,428 | 21.2 | 21.1–21.2 | 1141 | 20.9 | 20.7–21.0 | 4608 | 21.2 | 21.1–21.3 |
Nulliparous (%) | 7226 | 42.1 | 41.4–42.9 | 595 | 54.5 | 51.5–57.4 | 1726 | 40.9 | 39.4–42.3 |
History of reproductive therapy (%) | 925 | 4.9 | 4.6–5.3 | 73 | 6.2 | 5.0–7.8 | 259 | 5.5 | 4.9–6.2 |
Regular use of any medicine (%) | 1956 | 10.3 | 9.8–10.7 | 139 | 11.3 | 9.7–13.2 | 519 | 11.0 | 10.1–11.9 |
Regular use of any supplement (%) | 5852 | 30.7 | 30.0–31.3 | 378 | 30.8 | 28.3–33.5 | 1565 | 33.1 | 31.8–34.5 |
Drinking habit at 1st trimester (%) | 2180 | 11.7 | 11.3–12.2 | 141 | 12.1 | 10.4–14.1 | 531 | 11.4 | 10.5–12.4 |
Smoking habit 1st trimester (%) | 2136 | 12.0 | 11.6–12.5 | 135 | 12.2 | 10.5–14.3 | 487 | 11.6 | 10.7–12.6 |
Passive smoking in house (%) | 11,752 | 65.9 | 65.2–66.6 | 687 | 61.2 | 58.3–64.0 | 2852 | 63.6 | 62.2–65.0 |
Education, compulsory education only (%) | 1011 | 5.4 | 5.1–5.7 | 74 | 6.4 | 5.1–7.9 | 247 | 5.3 | 4.7–6.0 |
Occupation, no job | 8137 | 41.6 | 40.9–42.3 | 499 | 40.7 | 38.0–43.5 | 2012 | 41.5 | 40.1–42.9 |
Income, <3,000,000 yen/year (%) | 3662 | 22.8 | 22.2–23.5 | 240 | 23.8 | 21.2–26.5 | 916 | 22.7 | 21.4–24.0 |
Paternal characteristics | |||||||||
Age at entry (years) | 18,311 | 31.7 | 31.6–31.8 | 1135 | 31.1 | 30.8–31.4 | 4595 | 31.7 | 31.5–31.9 |
Drinking habit (%) | 13,375 | 72.1 | 71.5–72.8 | 863 | 75.2 | 72.6–77.6 | 3319 | 71.5 | 70.2–72.8 |
Smoking habit 1st trimester (%) | 10,855 | 66.4 | 65.7–67.1 | 650 | 64.3 | 61.3–67.2 | 2644 | 65.0 | 63.5–66.4 |
Education, compulsory education only (%) | 1431 | 7.8 | 7.4–8.2 | 78 | 6.9 | 5.6–8.5 | 347 | 7.5 | 6.8–8.3 |
Occupation, no job | 417 | 2.2 | 2.0–2.4 | 41 | 3.4 | 2.6–4.7 | 117 | 2.5 | 2.0–3.0 |
Outcomes | Number | Percent | 95% CI |
---|---|---|---|
Miscarriagea
| 200 | 1.1 | 0.9–1.2 |
Artificial abortionb
| 52 | 0.28 | 0.21–0.36 |
Stillbirthc
| 60 | 0.32 | 0.24–0.41 |
Live birth | 18,570 | 98.3 | 98.2–98.5 |
Preterm birthd
| 923 | 4.9 | 4.6–5.2 |
Moderate preterm birth | 795 | 4.2 | 3.9–4.5 |
Very preterm birth | 112 | 0.59 | 0.49–0.71 |
Extremely preterm birth | 47 | 0.24 | 0.18–0.33 |
Low birth weighte
| 1693 | 9.0 | 8.6–9.4 |
Very low birth weight | 268 | 1.4 | 1.2–1.6 |
Extremely low birth weight | 204 | 1.1 | 0.9–1.2 |
Macrosomiaf
| 190 | 1.0 | 0.9–1.2 |
Small for gestational ageg
| 1308 | 7.0 | 6.7–7.4 |
Term small for gestational ageh
| 1211 | 6.5 | 6.2–6.9 |
Small for reference fetal weighti
| 814 | 4.8 | 4.5–5.2 |
Exposure levels of environmental chemicals
Percentile | ||||||||
---|---|---|---|---|---|---|---|---|
Number | DL | >DL (%) | Min | 25th | 50th | 75th | Max | |
Maternal blood | ||||||||
Total dioxins (TEQ pg/g lipid) | 426 | n/a | n/a | 3.17 | 9.95 | 13.9 | 18.2 | 43.4 |
Total PCBs (ng/g lipid) | 426 | n/a | n/a | 17.8 | 73.0 | 107 | 148 | 41,460 |
p,p′-DDE | 379 | 0.60 | 100 | 99.52 | 401.53 | 650.99 | 1011.48 | 4575.67 |
PFOS (ng/mL) | 447 | 0.5 | 100 | 1.30 | 3.40 | 5.20 | 7.00 | 16.2 |
PFOA (ng/mL) | 447 | 0.5 | 92.8 | 0.25 | 0.80 | 1.30 | 1.80 | 5.30 |
MEHP (ng/mL) | 493 | 0.278 | 100 | 1.94 | 5.82 | 9.95 | 16.3 | 101.7 |
Bisphenol A (ng/mL) | 59 | 0.04 | 76.3 | <DL | 0.040 | 0.057 | 0.072 | 0.419 |
Cord blood | ||||||||
Bisphenol A (ng/mL) | 285 | 0.04 | 68.8 | <DL | <DL | 0.051 | 0.076 | 0.217 |
Maternal hair | ||||||||
Me-Hg (μg/g) | 430 | n/a | 100 | 0.24 | 0.96 | 1.40 | 1.89 | 7.55 |
Health effects
Birth size
Exposures | Outcome | Number | Findings | Reference |
---|---|---|---|---|
PCDD/PCDFs | Birth weight | 398 | Significant decrease. Individual congener assessment found 2,3,4,7,8-PeCDF had a significant negative influence (per log10 unit: β = −24.5 g, 95% CI −387.4 to −61.5). | [33] |
PCBs | Birth weight | 367 | No association. | [36] |
PFASs | Birth weight | 428 | PFOS was negatively correlated (per log10 unit: β = −269.4 g, 95% CI −465.7 to −73.0). | [34] |
Ponderal index | 177 | PFOA was negatively associated (per log10 unit: β = −0.73 kg/m3, 95% CI −1.44 to −0.02). | [26] | |
Cord adipokines | 168 | PFOS was positively associated with adiponectin (per log10 unit: β = 0.12, 95% CI 0.01 to 0.22). | [37] | |
DEHP | Ponderal index | 167 | Significant decrease (per log10 unit: β = −1.28, 95% CI −2.43 to −0.13). | [35] |
Cord adipokines | 167 | Significant decrease in leptin among girls (per log10 unit: β = −0.31, 95% CI −0.52 to −0.10). Significant increase in adiponectin among boys (per log10 unit: β = 4.63, 95% CI 0.77 to 8.49). | ||
Me-Hg | Birth weight/SGA | 367 | No association with birth weight. The risk of SGA by weight decreased with increasing Me-Hg. | [36] |
Thyroid, reproductive, and steroid hormone levels
Exposures | Outcome | Number | Findings | Reference |
---|---|---|---|---|
PFAS | Maternal/infant TSH, FT4 | 392 | Maternal PFOS levels were inversely correlated with maternal serum TSH and positively associated with infant serum TSH levels, whereas maternal PFOA showed no significant relationship with TSH or FT4 levels among mothers and infants. | [38] |
DEHP | Infant TSH, FT4 | 328 | No association. | [39] |
Bisphenol A | Infant TSH, FT4 | 285 | No association. | [40] |
PCB | Infant TSH, FT4 | 358 | Log10 Σdioxin (TEQ) was associated with increased FT4 (β = 0.224 ng/dL, 95% CI 0.016 to 0.433) overall, and the association was more significant among boys (β = 0.299 ng/dL, 95% CI 0.011 to 0.587). | [41] |
PFASs | Cord reproductive hormones | 189 | PFOS levels were positively associated with E2 and T/E2 and inversely with P4; inhibin B and PFOA levels were positively associated with inhibin B levels in boys. Significant inverse associations were observed between PFOS levels and P4 and PRL levels in girls. | [45] |
Cord steroid hormones | 185 | Cortisol and cortisone reduced in association with PFOS level (Q4 vs. Q1: β = −23.98 ng/mL, 95% CI −47.12 to −11.99; β = −63.21 ng/mL, 95% CI −132.56 to −26.72). DEHA increased (Q4 vs. Q1: β = 1.33 ng/mL, 95% CI 0.17 to 1.82). DHEA decreased (Q4 vs. Q1: β = −1.23 ng/mL, 95% CI −1.72 to −0.25) in association with PFOA. | [44] | |
DEHP | Cord reproductive hormones | 202 | MEHP was associated with reduced levels of T/E2, P4, and inhibin B. Inverse associations between maternal MEHP levels T/E2, P4, inhibin B, and INSL3 for males. | [42] |
Cord steroid hormones | 202 | MEHP was associated with reduced cortisol and cortisone levels and glucocorticoid/adrenal androgen ratio whereas increased DHEA levels and DHEA/androstenedione ratio. | [43] | |
Bisphenol A | Cord reproductive hormones | 285 | Negatively associated with PRL (β = −0.38). | [40] |
Neurobehavioral development
Exposures | Outcome | Age at testing | Number | Findings | Reference |
---|---|---|---|---|---|
Sapporo cohort | |||||
PCDD/PCDFs | BSID-II | 6 months | 134 | Several dioxin isomers showed adverse effects on motor development in 6-month-old male infants. | [46] |
PCDD/PCDFs, PCBs | BSID-II | 18 months | 190 | At 18 months of age, the associations observed at 6 months disappeared. The levels of six dioxin isomers were significantly positively associated with mental development in 18-month-old girls. | [49] |
PFASs | BSID-II | 6 and 18 months | 173 | PFOA was negatively associated with mental development in 6-month-old girls (per log10 unit: β = −0.296, 95% CI −11.96 to −0.682). | [47] |
DEHP | BSID-II | 6 and 18 months | 328 | Not associated. | [39] |
Bisphenol A | BSID-II, CBCL, K-ABC | 6 and 18 months 3.5 years 3.5 years | 285 | Not associated with mental and psychomotor development, but associated with internalizing problems at 42 months (per log10 unit: β = 4.37, 95% CI 0.11 to 8.64). | [48] |
SES | K-ABC | 3.5 years | 145 | Family income is an optimum indicator of SES in the association with intellectual ability in Japanese children aged 42 months. | [51] |
Hokkaido cohort | |||||
SES | SDQ | 5 years | 2553 | Maternal prepregnancy BMI ≥30 kg/m2, primipara, maternal education ≤high school, family income during pregnancy <3 million yen/year, and boy gender were the factors associated with increased odds ratio of the likelihood of child behavioral problems. | [50] |
Allergies and infectious diseases
Exposures | Outcome | Number | Findings | Reference |
---|---|---|---|---|
Sapporo cohort | ||||
Dioxins | Otitis media | 364 | Polychlorinated dibenzofuran was associated with increased risk among male infants (OR 2.5, 95% CI 1.1–5.9). 2,3,4,7,8-pentachlorodibenzo-furan was associated with increased risk of otitis media (OR 5.3, 95% CI 1.5–19). | [53] |
PFASs | Cord IgE/infectious disease | 343 | Cord IgE levels decreased with high maternal PFOA concentration among females. No associations among maternal PFOS and PFOA levels and food allergy, eczema, wheezing, or otitis media in the 18-month-old infants. | [54] |
Hokkaido cohort | ||||
PFASs | Eczema | 2063 | At 24 months, the risk in association with higher maternal PFTrDA levels decreased (OR 0.62, 95% CI 0.45–0.86). | [32] |
Total allergic diseases/eczema/wheezing | 1558 | ORs in the Q4 vs. Q1 for total allergic diseases decreased for PFDoDA (OR 0.621, 95% CI 0.454–0.847) and PFTrDA (OR 0.712, 95% CI 0.524–0.966). OR (Q4 vs. Q1) for wheezing in relation to higher maternal PFHxS levels was 0.728 (95% CI 0.497–1.06). | [56] | |
Infectious diseases | 1558 | PFHxS was associated with higher risk of total infections disease among girls (Q1 vs. Q4: OR 1.55, 95% CI 0.976–2.45). | [55] |
Maternal fatty acid concentrations during pregnancy
Effects of exposure and gene polymorphisms
Environmental exposure | Maternal genetic polymorphism | Maternal risk genotypes | Birth weight reduction (g) | Reference |
---|---|---|---|---|
Active smoking |
AhR (G>A, Arg554Lys) | Arg/Arg |
−211 | [22] |
CYP1A1 (m1/m2) | m1/m2 + m2/m2 |
−170 | ||
GSTM1 (non-null/null) | Null |
−171 | ||
Combination with AhR (G>A, Arg554Lys) and CYP1A1 (m1/m2) | Arg/Arg (AhR) and m1/m2 + m2/m2 (CYP1A1) |
−315 | ||
Combination with CYP1A1 (m1/m2) and GSTM1 (non-null/null) | m1/m2 + m2/m2 (CYP1A1) and null (GSTM1) |
−237 | ||
NQO1 (C>T, Pro187Ser) | Pro/Pro |
−159 | [62] | |
CYP2E1 (c1/c2) | c1/c1 |
−195 | ||
MTHFR (A1298C) | AA |
−106 | [63] | |
CYP1A1 (A>G, Ile462Val) | AG/GG |
−62 | [61] | |
XRCC1 (C>T, Arg194Trp) | CT/TT |
−59 | ||
Combination with AhR (G>A, Arg554Lys), CYP1A1 (A>G, Ile462Val), and XRCC1 (C>T, Arg194Trp) | GG (AhR), AG/GG (CYP1A1), and CT/TT (XRCC1) |
−145 | ||
Dioxin (total TEQ) |
GSTM1 (non-null/null) | Null |
−345 | [59] |