Relationship between pesticides and metabolic syndrome: no coincidence

Metabolic syndrome referred to by the acronyms SMet (for metabolic syndrome) or MetS (for Metabolic syndrome in English speakers) refers to the association of a series of health problems with similarly poor metabolism in old.
It is one of the emergent syndromes. We cannot say that it is a disease: rather a group of risk factors that are more or less involved in a single origin, metabolic targets or common mechanisms. However, there is consensus on the fact that metabolic syndrome detected in a person with no expressed symptoms equals a risk of cardiovascular accident multiplied by three compared to a truly healthy individual.

Metabolic syndrome describes a condition that describes many serious diseases:

  • Type 2 diabetes, which has for example a seven -fold higher risk of Finns carrying SMET than the rest of the population;
  • Cardiovascular pathologies;
  • Stroke; risk 1.26 to 2.2 times higher according to the WHO, with less strict methodological bases.

According to this meta-analysis, pesticide exposure is an independent risk factor in the development of metabolic syndrome. The level of evidence is satisfactory for organochlorine, usually hexachlorocyclohexane, but it is insufficient for other types of pesticide. The risk appears to be higher in more recent studies, suggesting a likely increase in pesticide use over time. The level of evidence is high regarding the increased risk of diabetes and obesity associated with pesticide exposure, but the relationship between pesticide exposure and metabolic syndrome is not clearly described. This systematic review and meta-analysis enhances knowledge on this topic.

The review focused on all studies published prior to October 2021 and reported the risk of metabolic syndrome associated with exposure to pesticides. A total of 12 studies (n = 6789) were included in the meta-analysis, with 29.1% of subjects with MetS. Everyone is at low risk of discrimination. Half were cross-sectional studies, in addition to 3 nested case-control studies, 2 cohort studies and 1 case-control study. Each included 100 to 1,162 subjects.

Total exposure to pesticides and their contaminants increases the risk of MetS by 30%. Organochlorines increase the risk of metabolic syndrome by 23%. Among them, hexachlorocyclohexane was the most specific to increase risk (53%), followed by oxychlordane (50%), transnonchlor (56%) and hexachlorobenzene (40%). Pesticide contaminants increased the risk by 31%, primarily PCBs (32%). Sensitivity analyzes confirmed that aggregate exposure to pesticides and their contaminants increased the risk by 46% using raw data or 19% using a fully appropriate model. Meta-regressions showed that hexachlorocyclohexane increased the risk of MetS significantly more than other pesticides.

The risk of pesticide-related metabolic syndrome has increased in the most recent studies (coefficient of 0.28 per year). In addition, a higher BMI or waist circumference reduces the risk of metabolic syndrome after exposure to pesticides, which can be explained by the storage of pesticides in adipose tissue. In the end, the risk is lower in men.

All these conclusions are not small for Reunion, where exposure to pesticides is one of the highest in France: it appears to be one of the explanations for the high incidence of metabolic diseases on our island. It is time to wake up to fight against bad agricultural practices in Reunion.

Here is a summary of the article:

The relationship between pesticide exposure and metabolic syndrome (MetS) has not yet been clearly identified. In a systematic review and meta-analysis, PubMed, Cochrane Library, Embase and ScienceDirect were sought for studies reporting the risk of MetS from exposure to pesticides and their contaminants. We included 12 studies with a total of 6789 participants, of which 1981 (29.1%) had MetS. Aggregate exposure to pesticides and their contaminants increases the risk of MetS by 30%(95CI 22%–37%). In general, organochlorines increase the risk of MetS by 23% (14-32%), as well as for most types of organochlorines: hexachlorocyclohexane increases the risk by 53% (28-78%), 40 % hexachlorobenzene (0.01–80%), 22% dichlorodiphenyldichloroethylene (9–34%), 28% dichlorodiphenyltrichloroethane (5–50%), 24% oxychlordane (1–47%), and 35% transnonchlor (19–52%). Sensitivity analyzes confirmed that aggregate exposure to pesticides and their contaminants increased the risk by 46% (35-56%) using raw data or 19% (10-29%) using a perfectly fit model. The risk of all pesticides and types of pesticide is also important in the raw data, but only for hexachlorocyclohexane (36% risk increase, 17-55%) and transnonchlor (25% risk increase, 3-48%). there are perfectly fitting models. Meta-regressions showed that hexachlorocyclohexane increased the risk of MetS compared to most other pesticides. The risk increased for more recent periods (Coefficient = 0.28, CI95 0.20 to 0.37, per year). We show an inverse relationship between body mass index and male gender. In conclusion, exposure to pesticides is a major risk factor for MetS. Aside from exposure to organochlorines, data are lacking for other types of pesticides. The risk has increased over time, indicating a likely increase in pesticide use worldwide. The inverse relationship of body mass index may mean the storage of pesticides and contaminants in fatty tissue.

Reference: https://pubmed.ncbi.nlm.nih.gov/35439599/

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