Obesity and risk for respiratory diseases: a Mendelian randomization study

Our plain-English summary of Obesity and risk for respiratory diseases: a Mendelian randomization study, by W. Yang, Y. Yang, Y. Guo, et al (Frontiers in Endocrinology, 2023).

The study

• Authors: W. Yang, Y. Yang, Y. Guo, J. Guo, M. Ma, B. Han
• Journal: Frontiers in Endocrinology
• Published: 2023;14:1197730
• Cited by: 51 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: No existing comprehensive Mendelian randomization studies have focused on how obesity affects respiratory diseases.

Methods: BMI and waist circumference, mainly from the UK Biobank, and 35 respiratory diseases from the FinnGen Biobank were subjected to Mendelian randomization analyses. In this study, the inverse variance weighting method was used as the predominant analysis method and was complemented by MR-Egger and weighted median methods. Horizontal pleiotropy and potential outliers were detected by employing the MR-PRESSO method.

Results: This study indicated that obesity rises the possibility of acute upper respiratory infections (BMI: OR=1.131, p<0.0001; WC: OR=1.097, p=0.00406), acute sinusitis (BMI: OR=1.161, p=0.000262; WC: OR=1.209, p=0.000263), acute pharyngitis (WC: OR=1.238, p=0.0258), acute laryngitis and tracheitis (BMI: OR=1.202, p=0.0288; WC: OR=1.381, p=0.00192), all influenza (BMI: OR=1.243, p=0.000235; WC: OR=1.206, p=0.0119), viral pneumonia (WC: OR=1.446, p=0.000870), all pneumoniae (BMI: OR=1.174, p <0.0001; WC: OR=1.272, p <0.0001), bacterial pneumoniae (BMI: OR=1.183, p=0.000290; WC: OR=1.274, p<0.0001), acute bronchitis (BMI: OR=1.252, p <0.0001; WC: OR=1.237, p=0.000268), acute unspecified lower respiratory infection (BMI: OR=1.303, p=0.000403), chronic tonsils and adenoids diseases (BMI: OR=1.236, p <0.0001; WC: OR=1.178, p=0.000157), chronic laryngotracheitis and laryngitis (WC: OR=1.300, p=0.00785), COPD (BMI: OR=1.429, p <0.0001; WC: OR=1.591, p <0.0001), asthma (BMI: OR=1.358, p <0.0001; WC: OR=1.515, p <0.0001), necrotic and suppurative conditions of lower respiratory tract (WC: OR=1.405, p=0.0427), pleural effusion (BMI: OR=1.277, p=0.00225; WC: OR=1.561, p<0.0001), pleural plaque (BMI: OR=1.245, p=0.0312), other diseases of the respiratory system (BMI: OR=1.448, p <0.0001; WC: OR=1.590, p <0.0001), and non-small cell lung cancer (BMI: OR=1.262, p=0.00576; WC: OR=1.398, p=0.00181). This study also indicated that obesity decreases the possibility of bronchiectasis (BMI: OR=0.705; p=0.00200).

Conclusion: This study revealed that obesity increases the risk of the majority of respiratory diseases (including 20 of all 35 respiratory diseases) and that obesity decreases the risk of bronchiectasis.

Copyright © 2023 Yang, Yang, Guo, Guo, Ma and Han.

In plain English

This was a Mendelian randomization study, which uses genetic variants as stand-ins for a trait. The authors used genetic data on body mass index (BMI, 681,275 people of European descent) and waist circumference (462,166 people, from the UK Biobank), and genetic data on 35 respiratory diseases from Finland's FinnGen Biobank. The study did not examine asbestos exposure. The authors reported that higher BMI or waist circumference raised the risk of 20 of the 35 diseases, including COPD, asthma, pneumonia, pleural effusion and non-small cell lung cancer. For pleural plaque (2,530 cases), the odds ratio was 1.245 (p=0.0312) for BMI. Waist circumference showed no statistically significant link with pleural plaque. Higher BMI was linked to lower risk of bronchiectasis (odds ratio 0.705). No link was found for 14 diseases, including lung diseases due to external agents and other pleural conditions. The authors concluded that obesity increases the risk of most respiratory diseases. They noted that their data could not detect U-shaped patterns, could not separate ages or sexes, and covered only European populations.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Two-sample Mendelian randomization study using published genetic association (GWAS) summary data, with inverse variance weighting as the main method
• Who was studied: Genetic summary data on European-descent individuals: 681,275 for BMI and 462,166 for waist circumference. Outcome data for 35 respiratory diseases came from FinnGen Biobank round 8, with 1,035 to 61,543 cases per disease. Pleural plaque had 2,530 cases and 328,786 controls.
• Exposure: Obesity, measured as genetically predicted body mass index and waist circumference. No asbestos or other occupational exposure was studied.
• Main results:
  • Pleural plaque was related to BMI (OR=1.245, p=0.0312) but not to waist circumference (p greater than 0.05). Acute upper respiratory infections of unspecified and multiple sites showed the same pattern (BMI: OR=1.126, p=0.000182).
  • COPD was related to both measures (BMI: OR=1.429, p less than 0.0001; waist circumference: OR=1.591, p less than 0.0001). So was asthma (BMI: OR=1.358, p less than 0.0001; waist circumference: OR=1.515, p less than 0.0001).
  • Pleural effusion was related to BMI (OR=1.277, p=0.00225) and to waist circumference (OR=1.561, p less than 0.0001).
  • Non-small cell lung cancer was related to BMI (OR=1.262, p=0.00576) and to waist circumference (OR=1.398, p=0.00181).
  • BMI was associated with a reduced risk of bronchiectasis (OR=0.705, p=0.00200). Waist circumference did not show this (OR=0.814, p=0.149).
  • Neither BMI nor waist circumference was related (p greater than 0.05) to several outcomes. These included lung diseases due to external agents (ICD-10 J60-J70 in Table 1), emphysema, pneumothorax and other pleural conditions.
  • Overall, obesity was related to increased risk for 20 of the 35 diseases, reduced risk for bronchiectasis, and no relationship for 14 diseases.
• The authors' conclusion: The authors concluded that obesity increases the risk of most respiratory diseases (20 of the 35 studied) and decreases the risk of bronchiectasis.
• Limitations the authors state:
  • Because BMI and waist circumference were analyzed as continuous measures, the study could not detect a U-shaped association, in which both high and low values raise risk.
  • The data did not separate people by age or sex.
  • Only European populations were included, so the findings may not apply to other populations.
  • The findings reflect long-term exposure to obesity. Short-term changes in obesity may not affect disease incidence.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer.

Medical terms in this study, explained in our Lexicon: COPD, Pleural Effusion, Pleural Plaques, Non-Small Cell Lung Cancer.

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