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Association of Childhood Lead Exposure With Adult Personality Traits and Lifelong Mental Health (2019) Reuben et al

Discussion in 'Other health news and research' started by Colin, Mar 22, 2021.

  1. Colin

    Colin Established Member (Voting Rights)

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    Location:
    Brisbane, Australia
    Key Points

    Question Is childhood lead exposure associated with the risk of mental illness or difficult personality traits in adulthood?

    Findings In this longitudinal cohort study of 579 New Zealand children followed up for more than 30 years, greater lead exposure in childhood was significantly associated with greater psychopathology across the life course and with difficult personality traits in adulthood.

    Meaning Childhood lead exposure may have long-term consequences for adult mental health and personality.

    Abstract

    Importance
    Millions of adults now entering middle age were exposed to high levels of lead, a developmental neurotoxin, as children. Although childhood lead exposure has been linked to disrupted behavioral development, the long-term consequences for adult mental and behavioral health have not been fully characterized.

    Objective To examine whether childhood lead exposure is associated with greater psychopathology across the life course and difficult adult personality traits.

    Design, Setting, and Participants This prospective cohort study was based on a population-representative birth cohort of individuals born between April 1, 1972, and March 31, 1973, in Dunedin, New Zealand, the Dunedin Multidisciplinary Health and Development Study. Members were followed up in December 2012 when they were 38 years of age. Data analysis was performed from March 14, 2018, to October 24, 2018.

    Exposures Childhood lead exposure ascertained as blood lead levels measured at 11 years of age. Blood lead levels were unrelated to family socioeconomic status.

    Main Outcomes and Measures Primary outcomes were adult mental health disorder symptoms assessed through clinical interview at 18, 21, 26, 32, and 38 years of age and transformed through confirmatory factor analysis into continuous measures of general psychopathology and internalizing, externalizing, and thought disorder symptoms (all standardized to a mean [SD] of 100 [15]) and adult personality assessed through informant report using the Big Five Personality Inventory (assessing neuroticism, extraversion, openness to experience, agreeableness, and conscientiousness) at 26, 32, and 38 years of age (all scores standardized to a mean [SD] of 0 [1]). Hypotheses were formulated after data collection; an analysis plan was posted in advance.

    Results Of 1037 original study members, 579 (55.8%) were tested for lead exposure at 11 years of age (311 [53.7%] male). The mean (SD) blood lead level was 11.08 (4.96) μg/dL. After adjusting for study covariates, each 5-μg/dL increase in childhood blood lead level was associated with a 1.34-point increase (95% CI, 0.11-2.57; P = .03) in general psychopathology, driven by internalizing (b = 1.41; 95% CI, 0.19-2.62; P = .02) and thought disorder (b = 1.30; 95% CI, 0.06-2.54; P = .04) symptoms. Each 5-μg/dL increase in childhood blood lead level was also associated with a 0.10-SD increase in neuroticism (95% CI, 0.02-0.08; P = .02), a 0.09-SD decrease in agreeableness (95% CI, −0.18 to −0.01; P = .03), and a 0.14-SD decrease in conscientiousness (95% CI, −0.25 to −0.03; P = .01). There were no statistically significant associations with informant-rated extraversion (b = −0.09; 95% CI, −0.17 to 0.004; P = .06) and openness to experience (b = −0.07; 95% CI, −0.17 to 0.03; P = .15).

    Conclusions and Relevance In this multidecade, longitudinal study of lead-exposed children, higher childhood blood lead level was associated with greater psychopathology across the life course and difficult adult personality traits. Childhood lead exposure may have long-term consequences for adult mental health and personality.

    Open Access: JAMA Psychiatry
     
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  2. Colin

    Colin Established Member (Voting Rights)

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    Location:
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    Science Daily: Childhood lead exposure linked to poor adult mental health

    BBC WS: Health Check: Another week, another Covid-19 vaccine success (21:08m-32:19m)

    The Health Check item is an interview with Aaron Reuben, the lead author of this paper.

    This paper was based on data from the long-running, longitudinal study, "The Dunedin Multidisciplinary Health and Development Study", often called simply "the Dunedin study" and is interesting in that it shows a small association of "adult psychopathology and personality difficulties" with childhood exposure to lead, even 30 years after the exposure, even if there was no current, lead burden detectable. But while the focus was on mental health, they didn't find any association with fatigue or ME/CFS-like symptoms.
     
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  3. Hutan

    Hutan Moderator Staff Member

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    26,520
    Location:
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    That 11 micrograms/dL is surprisingly high. Parts of Dunedin have recently been reported as having unsafe lead levels in water.

    From another article on the study:
    A good example of how values of toxins that trigger concern and various actions can vary quite a bit over time and from place to place.

    I do wonder though if there wasn't a bit more confounding going on than is suggested. The researchers felt that the lead in petrol affected every suburb equally. But the poor kids (more likely to be exposed to a range of risk factors) probably were more likely to be playing or walking to school near busy streets, or living in an old house with peeling paint. I haven't read the full paper.
     
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  4. Colin

    Colin Established Member (Voting Rights)

    Messages:
    92
    Location:
    Brisbane, Australia
    But that's the value of the Dunedin study in that they did have the lead-levels, from whatever sources, from across the social cohorts and they do seem confident that they could pull that association out of it. But there is some iffiness regarding some questions as the lead author admits in the interview.

    But there could, as you say, be confounding factors, and one is the fine particulate matter from exhausts. The lead might be only be a proxy for it; though one would then have to suppose that exhausts were the main exposure, not paints and whatnot. Then again, there is more of the fine particulates in deisel exhausts but that doesn't have lead added to it. One could cop a lot of it, which can get into the brain and make the blood-brain barrier more permeable but not necessarily get a lot of lead. That probably isn't a common experience but I have thought about it quite a bit as I grew up working in a truck-yard workshop routinely breathing clouds of black smoke from old, deisel trucks. But I was probably exposed to a fair bit of lead, too.

    Whatever, the upshot of it seems to be that they found nothing that would indicate that childhood, lead-poisoning predisposes one to ME/CFS (though fatigue and cognitive problems are, of course, amongst the symptoms of lead poisoning).
     
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