Association Between Maternal Exposure to Magnetic Field Nonionizing Radiation During Pregnancy and Risk of Attention-Deficit/Hyperactivity Disorder in Offspring in a Longitudinal Birth Cohort

Abstract

Association Between Maternal Exposure to Magnetic Field Nonionizing Radiation During Pregnancy and Risk of Attention-Deficit/Hyperactivity Disorder in Offspring in a Longitudinal Birth Cohort Li DK, Chen H, Ferber JR, Hirst AK, Odouli R. Association Between Maternal Exposure to Magnetic Field Nonionizing Radiation During Pregnancy and Risk of Attention-Deficit/Hyperactivity Disorder in Offspring in a Longitudinal Birth Cohort. JAMA Netw Open. 2020 Mar 2;3(3):e201417. doi: 10.1001/jamanetworkopen.2020.1417. Abstract Importance: An association between maternal exposure to magnetic field (MF) nonionizing radiation during pregnancy and the risk of attention-deficit/hyperactivity disorder (ADHD) has been reported in both animal and human studies. Objectives: To determine whether maternal exposure to high levels of MF nonionizing radiation is associated with an increased risk of ADHD in offspring by using more accurate measurements of MF nonionizing radiation levels and physician-diagnosed ADHD, rather than self-reports, and to determine whether the association differs for the subtypes of ADHD with or without immune-related comorbidities. Design, Setting, and Participants: A longitudinal birth cohort study was conducted at Kaiser Permanente Northern California among 1482 mother-child pairs whose mothers were participants of an existing birth cohort and whose level of exposure to MF nonionizing radiation was captured during pregnancy in 2 studies conducted from October 1, 1996, to October 31, 1998, and from May 1, 2006, to February 29, 2012. The offspring were followed up from May 1, 1997, to December 31, 2017. Exposure: All participating women wore a monitoring meter for 24 hours during pregnancy to capture the level of exposure to MF nonionizing radiation from any sources. Main Outcomes and Measures: Physician-diagnosed ADHD and immune-related comorbidities of asthma or atopic dermatitis up to 20 years of age in offspring captured in the Kaiser Permanente Northern California electronic medical record from May 1, 1997, to December 31, 2017. Confounders were ascertained during in- person interviews during pregnancy. Results: Among the 1454 mother-child pairs (548 white [37.7%], 110 African American [7.6%], 325 Hispanic [22.4%], 376 Asian or Pacific Islander [25.9%], and 95 other or unknown [6.5%]; mean [SD] maternal age, 31.4 [5.4] years]), 61 children (4.2%) had physician-diagnosed ADHD. Using Cox proportional hazards regression to account for follow-up time and confounders, compared with children whose mothers had a low level of exposure to MF nonionizing radiation during pregnancy, children whose mothers were exposed to higher levels of MF nonionizing radiation had more than twice the risk of ADHD (adjusted hazard ratio [aHR], 2.01; 95% CI, 1.06-3.81). The association was stronger for ADHD that persisted into adolescence (≥12 years of age), with an aHR of 3.38 (95% CI, 1.43-8.02). When the subtypes of ADHD were examined, the association existed primarily for ADHD with immune-related comorbidities (asthma or atopic dermatitis), with an aHR of 4.57 (95% CI, 1.61- 12.99) for all ADHD cases and an aHR of 8.27 (95% CI, 1.96-34.79) for persistent cases of ADHD. Conclusions and Relevance: Consistent with the emerging literature, this study suggests that in utero exposure to high levels of MF nonionizing radiation was associated with an increased risk of ADHD, especially ADHD with immune-related comorbidity. The findings should spur more research to examine the biological association of in utero MF exposure with risk of ADHD in offspring, given that almost everyone is exposed to it. Excerpts Approximately 11% of all children aged 4 to 17 years (>6.4 million children) in the United States receive a diagnosis of, or treatment for, attention-deficit/hyperactivity disorder (ADHD). Attention-deficit/hyperactivity disorder has been associated with poor school performance during childhood and with lifelong disabilities.... One nonchemical factor that has not been examined is the ever-present nonionizing radiation, also known as magnetic fields (MFs), emitted from electric appliances, power lines, and wireless devices and networks including cell phone towers.... Once a pregnant woman had given consent to participate in the study, she was asked to wear an EMDEX meter (Enertech Inc) to capture the level of MF nonionizing radiation exposure. During the 24-hour monitoring period, which occurred during the first or second trimester, the meters (EMDEX II and EMDEX Lite) captured levels of 40 to 800 Hz of MF nonionizing radiation encountered by the participating woman throughout her daily life. The MF nonionizing radiation level was measured in milligauss.... To examine the association of high levels of MF nonionizing radiation with risk of ADHD, we used the 90th percentile of the 24-hour measurements as the MF index, which reflects the MF nonionizing radiation level at or above which a participant was exposed to for 10% of the time during the day. Given that everyone is exposed to MF nonionizing radiation at some levels, to classify participating women into low or high MF nonionizing radiation exposure groups, based on the experience of previous studies,9,10,19 we used a cutoff based on the 25th percentile of the MF index's distribution, which corresponded to 1.3 mG. The participants whose MF nonionizing radiation level was lower than 1.3 mG were classified as having a low level of MF nonionizing radiation exposure during pregnancy, while the participants whose MF nonionizing radiation level was 1.3 mG or higher were classified as having a relatively higher daily level of MF nonionizing radiation exposure. Conclusions Using a longitudinal birth cohort study design, we examined the association between maternal exposure to MF nonionizing radiation during pregnancy and risk of ADHD in offspring throughout childhood up to age 20 years. The study improved over previous studies by enhancing the accuracy of measuring MF nonionizing radiation exposure and of ADHD diagnosis. The findings provide new evidence that in utero exposure to a high level of MF nonionizing radiation is associated with an increased risk of ADHD in offspring. The association is primarily between MF nonionizing radiation exposure and ADHD with immune-related comorbidities and persistent cases of ADHD. The findings reveal a possible new risk factor that is ubiquitous in our modern day lives and should spur more research to examine this potential association. Open access paper: ncbi.nlm.nih.gov

AI evidence extraction

Main findings

In Cox proportional hazards models adjusted for confounders, offspring of mothers with higher prenatal magnetic field exposure had higher risk of physician-diagnosed ADHD than those with low exposure (aHR 2.01; 95% CI 1.06-3.81). The association was stronger for ADHD persisting into adolescence (aHR 3.38; 95% CI 1.43-8.02) and appeared primarily for ADHD with immune-related comorbidities (aHR 4.57; 95% CI 1.61-12.99; persistent cases aHR 8.27; 95% CI 1.96-34.79).

Outcomes measured

• Physician-diagnosed ADHD in offspring up to 20 years of age
• ADHD persistence into adolescence (≥12 years)
• ADHD with immune-related comorbidities (asthma or atopic dermatitis)

Limitations

• Exposure sources not separated (meter captured MF exposure from any sources)
• Exposure assessed over a single 24-hour period during pregnancy
• Relatively small number of ADHD cases (61) leading to wide confidence intervals, especially in subtype analyses

Suggested hubs

• elf-power-lines (0.72)
  Exposure was extremely low frequency magnetic fields (40–800 Hz) measured in milligauss, with sources including electric appliances and power lines.
• prenatal-exposure (0.7)
  Maternal MF exposure measured during pregnancy and linked to offspring neurodevelopmental outcome (ADHD).
• occupational-exposure (0.2)
  Personal monitoring captured exposure throughout daily life; occupational contribution not specified but could be included within 'any sources'.

{
    "study_type": "cohort",
    "exposure": {
        "band": "ELF",
        "source": "mixed/any sources (electric appliances, power lines, wireless devices and networks)",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "24-hour personal monitoring during pregnancy (first or second trimester)"
    },
    "population": "Mother-child pairs in Kaiser Permanente Northern California birth cohort (pregnant women and offspring followed up to age 20 years)",
    "sample_size": 1454,
    "outcomes": [
        "Physician-diagnosed ADHD in offspring up to 20 years of age",
        "ADHD persistence into adolescence (≥12 years)",
        "ADHD with immune-related comorbidities (asthma or atopic dermatitis)"
    ],
    "main_findings": "In Cox proportional hazards models adjusted for confounders, offspring of mothers with higher prenatal magnetic field exposure had higher risk of physician-diagnosed ADHD than those with low exposure (aHR 2.01; 95% CI 1.06-3.81). The association was stronger for ADHD persisting into adolescence (aHR 3.38; 95% CI 1.43-8.02) and appeared primarily for ADHD with immune-related comorbidities (aHR 4.57; 95% CI 1.61-12.99; persistent cases aHR 8.27; 95% CI 1.96-34.79).",
    "effect_direction": "harm",
    "limitations": [
        "Exposure sources not separated (meter captured MF exposure from any sources)",
        "Exposure assessed over a single 24-hour period during pregnancy",
        "Relatively small number of ADHD cases (61) leading to wide confidence intervals, especially in subtype analyses"
    ],
    "evidence_strength": "moderate",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "magnetic field",
        "nonionizing radiation",
        "ELF",
        "pregnancy",
        "in utero exposure",
        "ADHD",
        "attention-deficit/hyperactivity disorder",
        "birth cohort",
        "EMDEX meter",
        "asthma",
        "atopic dermatitis",
        "immune-related comorbidity"
    ],
    "suggested_hubs": [
        {
            "slug": "elf-power-lines",
            "weight": 0.7199999999999999733546474089962430298328399658203125,
            "reason": "Exposure was extremely low frequency magnetic fields (40–800 Hz) measured in milligauss, with sources including electric appliances and power lines."
        },
        {
            "slug": "prenatal-exposure",
            "weight": 0.6999999999999999555910790149937383830547332763671875,
            "reason": "Maternal MF exposure measured during pregnancy and linked to offspring neurodevelopmental outcome (ADHD)."
        },
        {
            "slug": "occupational-exposure",
            "weight": 0.200000000000000011102230246251565404236316680908203125,
            "reason": "Personal monitoring captured exposure throughout daily life; occupational contribution not specified but could be included within 'any sources'."
        }
    ]
}

Comments

Log in to comment.

No comments yet.