Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 Feb;75(2):79-89.
doi: 10.1136/oemed-2017-104431. Epub 2017 Aug 3.

Occupational Pesticide Exposure and Subclinical Hypothyroidism Among Male Pesticide Applicators

Affiliations
Free PMC article

Occupational Pesticide Exposure and Subclinical Hypothyroidism Among Male Pesticide Applicators

Catherine C Lerro et al. Occup Environ Med. .
Free PMC article

Abstract

Objectives: Animal studies suggest that exposure to pesticides may alter thyroid function; however, few epidemiologic studies have examined this association. We evaluated the relationship between individual pesticides and thyroid function in 679 men enrolled in a substudy of the Agricultural Health Study, a cohort of licensed pesticide applicators.

Methods: Self-reported lifetime pesticide use was obtained at cohort enrolment (1993-1997). Intensity-weighted lifetime days were computed for 33 pesticides, which adjusts cumulative days of pesticide use for factors that modify exposure (eg, use of personal protective equipment). Thyroid-stimulating hormone (TSH), thyroxine (T4), triiodothyronine (T3) and antithyroid peroxidase (anti-TPO) autoantibodies were measured in serum collected in 2010-2013. We used multivariate logistic regression to estimate ORs and 95% CIs for subclinical hypothyroidism (TSH >4.5 mIU/L) compared with normal TSH (0.4-<4.5 mIU/L) and for anti-TPO positivity. We also examined pesticide associations with TSH, T4 and T3 in multivariate linear regression models.

Results: Higher exposure to the insecticide aldrin (third and fourth quartiles of intensity-weighted days vs no exposure) was positively associated with subclinical hypothyroidism (ORQ3=4.15, 95% CI 1.56 to 11.01, ORQ4=4.76, 95% CI 1.53 to 14.82, ptrend <0.01), higher TSH (ptrend=0.01) and lower T4 (ptrend=0.04). Higher exposure to the herbicide pendimethalin was associated with subclinical hypothyroidism (fourth quartile vs no exposure: ORQ4=2.78, 95% CI 1.30 to 5.95, ptrend=0.02), higher TSH (ptrend=0.04) and anti-TPO positivity (ptrend=0.01). The fumigant methyl bromide was inversely associated with TSH (ptrend=0.02) and positively associated with T4 (ptrend=0.01).

Conclusions: Our results suggest that long-term exposure to aldrin, pendimethalin and methyl bromide may alter thyroid function among male pesticide applicators.

Keywords: agriculture; hypothyroidism; pesticides; thyroid disease; thyroid stimulating hormone.

Conflict of interest statement

Competing interests: None declared.

Similar articles

See all similar articles

Cited by 7 articles

See all "Cited by" articles

Publication types

Feedback