Infection with Soil-Transmitted Helminths Is Associated with Increased Insulin Sensitivity

PLoS One. 2015 Jun 10;10(6):e0127746. doi: 10.1371/journal.pone.0127746. eCollection 2015.

Abstract

Objective: Given that helminth infections have been shown to improve insulin sensitivity in animal studies, which may be explained by beneficial effects on energy balance or by a shift in the immune system to an anti-inflammatory profile, we investigated whether soil-transmitted helminth (STH)-infected subjects are more insulin sensitive than STH-uninfected subjects.

Design: We performed a cross-sectional study on Flores island, Indonesia, an area with high prevalence of STH infections.

Methods: From 646 adults, stool samples were screened for Trichuris trichiura by microscopy and for Ascaris lumbricoides, Necator americanus, Ancylostoma duodenale, and Strongyloides stercoralis by qPCR. No other helminth was found. We collected data on body mass index (BMI, kg/m2), waist-to-hip ratio (WHR), fasting blood glucose (FBG, mmol/L), insulin (pmol/L), high sensitive C-reactive protein (ng/ml) and Immunoglobulin E (IU/ml). The homeostatic model assessment for insulin resistance (HOMAIR) was calculated and regression models were used to assess the association between STH infection status and insulin resistance.

Results: 424 (66%) participants had at least one STH infection. STH infected participants had lower BMI (23.2 vs 22.5 kg/m2, p value = 0.03) and lower HOMAIR (0.97 vs 0.81, p value = 0.05). In an age-, sex- and BMI-adjusted model a significant association was seen between the number of infections and HOMAIR: for every additional infection with STH species, the HOMAIR decreased by 0.10 (p for linear trend 0.01). This effect was mainly accounted for by a decrease in insulin of 4.9 pmol/L for every infection (p for trend = 0.07).

Conclusion: STH infections are associated with a modest improvement of insulin sensitivity, which is not accounted for by STH effects on BMI alone.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Ancylostoma
  • Animals
  • Ascaris lumbricoides
  • Cross-Sectional Studies
  • Female
  • Helminthiasis / epidemiology*
  • Helminthiasis / immunology
  • Humans
  • Indonesia
  • Insulin Resistance*
  • Male
  • Middle Aged
  • Necator americanus
  • Prevalence
  • Soil / parasitology*
  • Strongyloides stercoralis
  • Trichuris

Substances

  • Soil

Grant support

This work was supported by The Royal Netherlands Academy of Arts and Science (KNAW) (Grant number KNAW-05-PP-35) https://www.knaw.nl/en, to AEW FH LJW MAP ES TS MY; European Commission (Grant number INCO-CT-2006-031714 and INCO-CT-2006-032436) http://ec.europa.eu/contracts_grants/grants_en.htm, to MY; The Prof. Dr. P.C. Flu Foundation, to MMMK and JJV. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.