Environmental exposure to pesticides and risk of thyroid diseases

[helvella]

Toxicol Lett. 2019 Aug 21. pii: S0378-4274(19)30231-0. doi: 10.1016/j.toxlet.2019.08.017. [Epub ahead of print]

Environmental exposure to pesticides and risk of thyroid diseases.

Requena M1, López A2, Hernández AF3, Parrón T4, Navarro Á2, Alarcón R1.

Author information

1 University of Almería School of Health Sciences, Almería, Spain.

2 Hospital Torrecárdenas, Almería, Spain.

3 Dept. Legal Medicine and Toxicology, University of Granada School of Medicine, Granada, Spain. Electronic address: [e-mail].

4 University of Almería School of Health Sciences, Almería, Spain; Andalusian Council of Health at Almería Province, Almería, Spain.

Abstract

Occupational and environmental exposure to pesticides has been associated with thyroid dysfunction, particularly changes in circulating thyroid hormone levels (T3, T4) and thyroid stimulating hormone (TSH). This study assessed the association between environmental exposure to pesticides and the risk of developing thyroid diseases. A population-based case-control study was carried out among Spanish populations living in areas categorized as of high or low pesticide use according to agronomic criteria, which were used as surrogates for environmental exposure to pesticides. The study population consisted of 79.431 individuals diagnosed with goiter, thyrotoxicosis, hypothyroidism, and thyroiditis (according to the International Classification of Diseases, Ninth Revision) and 1.484.257 controls matched for age, sex and area of residence. Data were collected from computerized hospital records for the period 1998 to 2015. Prevalence rates and risk of having thyroid diseases were significantly higher in areas with higher pesticide use, with a 49% greater risk for hypothyroidism, 45% for thyrotoxicosis, 20% for thyroiditis and 5% for goiter. Overall, this study indicates an association between increased environmental exposure to pesticides as a result of a greater agricultural use and diseases of the thyroid gland, thus supporting and extending previous evidence. This study also provides support to the methodology proposed for real-life risk simulation, thus contributing to a better understanding of the real life threat posed by exposure to multiple pesticides from different sources.

Copyright © 2019. Published by Elsevier B.V.

KEYWORDS:

case–control study; environmental chemicals; pesticides; thyroid diseases

PMID: 31445060

DOI: 10.1016/j.toxlet.2019.08.017

ncbi.nlm.nih.gov/pubmed/314...

[m7-cola]

This confirms what some of us have thought for years. And it’s not just agricultural pesticides which are implicated. The use of chemicals, such as flame retardants in the home, may be risk factors for thyroid problems. Thank you for posting.

[stiltzski]

Interesting. I developed problems just over a year after moving to the country where I was surrounded by fields growing crops.

[TSH110 in reply to stiltzski]

I grew up in an area of the UK with one of most important petrochemical industries and all my surviving siblings have thyroid problems. My mother, her sister and grandmother all had hypothyroidism but they did not come from this part of the UK. It is hard to know if the chemicals have had an effect but I can’t imagine they were good for us. Some days the air would smell like farted custard - god knows what was being discharged into the atmosphere to cause that stench for miles and miles everywhere - it was deffo chemicals being dumped. Happened very regularly. It is known the area has much higher levels of leukaemia and I think other cancers than the rest of the uk. My deceased sibling died of n.h.lymphoma and three other family members have had it, but not all of them lived in the same area.

[stiltzski in reply to TSH110]

I am so sorry to hear that TSH 110. Sending warm wishes.

[TSH110 in reply to stiltzski]

That is so kind of you. I used to get quite sad about it all but life goes on and at least we can get treatment for the thyroid problems. I am only well on NDT but the ones who are hypo love Levothyroxine which seems pretty effective for them. Not sure how the hyperthyroid one goes -never gets in touch these days. I take the view each day is a bonus and I jolly well ought to make the most of it. I was so ill before I was finally diagnosed I was lucky to pull through. Unlucky yet very lucky, life has been an interesting journey so far and one good thing is that my depression has vanished yet it plagued me for decades and even before I took NDT

[stiltzski in reply to TSH110]

I also ditched Levothyroxine and am also on NDT; also suffered from depression for years but no longer do. My GP doesn’t get any of it. You are an inspiration after all you have gone through.

[TSH110 in reply to stiltzski]

You are too kind! I notice you were lucky enough to see Dr Gordon Skinner prior to his sad and untimely death - he was amazing I wish I had seen him. I had to just go solo with help and advice given here to guide me - I am glad I had the courage to self medicate on NDT as it gave me back my life and actually improved some very long standing things like the depression. I often wonder when the hypothyroidism started perhaps as early as my 20’s. I seem to have been hyperthyroid for most if my 30’s then a gradual decline up to my 50’s when I finally got treatment. Although it was really horrid I see It as a very valuable experience that has changed me for the good bar the longer term health issues probably caused by being untreated for so long, which mostly I can deal with but are slowly worsening. It could just be age and genetics of course, who knows.

[Lucylockett30]

I had to leave my job when my symptoms became much worse after the office moving next to Petrochemical plant and other pollution, high levels of sulphur dioxide in the air made my asthma and hypo much worse had to go to casualty twice !!!!!! One of the worst polluted areas in Europe

[DippyDame]

I believe chemical pollution has been blamed for a non- genetic form of (acquired) thyroid hormone resistance..., at cellular level

The battle goes on....

[TSH110]

This interesting paper might in part explain why some chemicals in say pesticides would interfere with thyroid function. It seems insects plants and vertebrates use hormones that are very closely related and even interchangeable. I wondered if insects had a thyroid gland - I doubted it - it seems It is not known if insects create the hormones they need for things like metamorphosis internally or if they get them from plant sources but some pesticides are also very similar chemically speaking.

academic.oup.com/icb/articl...

[helvella Administrator Thyroid UK in reply to TSH110]

Some hints in this abstract:

Evolution of ligands, receptors and metabolizing enzymes of thyroid signaling.

ncbi.nlm.nih.gov/pubmed/283...

[TSH110 in reply to helvella]

Thanks for article link - I will have read of it. I had no idea about there being a similarity in hormones in plants and those used by insects to thyroid hormones.

[helvella Administrator Thyroid UK in reply to TSH110]

And worms!

Nuclear Hormone Receptors in Parasitic Platyhelminths

WenjieWu1Philip T.LoVerde

doi.org/10.1016/j.molbiopar...

Abstract

Nuclear receptors (NRs) belong to a large protein superfamily which includes intracellular receptors for secreted hydrophobic signal molecules, such as steroid hormones and thyroid hormones. They regulate development and reproduction in metazoans by binding to the promoter region of their target gene to activate or repress mRNA synthesis. Isolation and characterization of NRs in the parasitic trematode Schistosoma mansoni identified two homologues of mammalian thyroid receptor (TR). This was the first known protostome exhibiting TR homologues. Three novel NRs each possess a novel set of two DNA binding domains (DBD) in tandem with a ligand binding domain (LBD) (2DBD-NRs) isolated in Schistosoma mansoni revealed a novel NR modular structure: A/B-DBD-DBD-hinge-LBD. Full length cDNA of several NRs have been isolated and studied in the parasitic trematodes S. mansoni, S. japonicum and in the cestode Echinococcus multilocularis. The genome of the blood flukes S. mansoni, S. japonicum and S. haematobium, the liver fluke Clonorchis sinensis and the cestode Echinococcus multilocularis have been sequenced. Study of the NR complement in parasitic Platyhelminths will help us to understand the role of NRs in regulation of their development and understand the evolution of NR in animals.

sciencedirect.com/science/a...

[TSH110 in reply to helvella]

Thanks for this - they must be fundamental.

[helvella Administrator Thyroid UK in reply to TSH110]

My super-simplistic view is this:

Iodine is a very potent element and can affect a lot of biological processes at the most fundamental level.

In early life, some processes developed which would ensure that any iodine atoms were reacted with other substances to stop the iodine killing the organism.

The substances produced eventually became useful in various ways and started the path to what at least the vertebrates have now. Possibly the iodine atoms themselves had useful functions. Hence, the deiodination of T4 to T3, T3 to T2, etc., actually gave a way of delivering iodine atoms directly to cells where they are needed - but without causing harm to the blood cells, blood vessels, and everything else the iodine compunds come into contact with.

Probably grossly teleological and utter rubbish.

[TSH110]

Sounds like an interesting and feasible explanation to me - thanks for sharing