The causal relationship between obesity and skin and soft tissue infections: A two-sample Mendelian randomization study

Abstract

ObjectiveMany observational studies have shown that obesity strongly affects skin and soft tissue infections (SSTIs). However, whether a causal genetic relationship exists between obesity and SSTIs is unclear.MethodsA two-sample Mendelian randomization (MR) study was used to explore whether obesity is causally associated with SSTIs using a publicly released genome-wide association study (GWAS). An inverse-variance weighted (IVW) analysis was used as the primary analysis, and the results are reported as the odds ratios (ORs). Heterogeneity was tested using Cochran’s Q test and the I2 statistic, and horizontal pleiotropy was tested using the MR−Egger intercept and MR pleiotropy residual sum and outlier (MR-PRESSO).ResultsThe results of the MR analysis showed a positive effect of BMI on SSTIs (OR 1.544, 95% CI 1.399-1.704, P= 5.86 × 10-18). After adjusting for the effect of type 2 diabetes (T2D) and peripheral vascular disease (PVD), the positive effect still existed. Then, we further assessed the effect of BMI on different types of SSTIs. The results showed that BMI caused an increased risk of impetigo, cutaneous abscess, furuncle and carbuncle, cellulitis, pilonidal cyst, and other local infections of skin and subcutaneous tissues, except for acute lymphadenitis. However, the associations disappeared after adjusting for the effect of T2D and PVD, and the associations between BMI and impetigo or cellulitis disappeared. Finally, we assessed the effects of several obesity-related characteristics on SSTIs. Waist circumference, hip circumference, body fat percentage, and whole-body fat mass, excluding waist-to-hip ratio, had a causal effect on an increased risk of SSTIs. However, the associations disappeared after adjusting for the effect of BMI.ConclusionThis study found that obesity had a positive causal effect on SSTIs. Reasonable weight control is a possible way to reduce the occurrence of SSTIs, especially in patients undergoing surgery.

Causal relationship of obesity and adiposity distribution on risk of ventral hernia

“…It is worth noting the association between obesity and surgical site infection, and surgical site infection will lead to the occurrence of VH. 31 Our study showed that VAT rather than SAT was associated with a high risk of VH, and VAT might serve as a potential predictor of IH. A recently published meta-analysis showed that the prophylactic use of mesh to prevent IH in midline laparotomy could reduce the prevalence of IH and did not increase the prevalence of surgical site occurrence.…”

“…The debate persists regarding whether abdominal subcutaneous or visceral obesity plays a predominant role in IH development. It is worth noting the association between obesity and surgical site infection, and surgical site infection will lead to the occurrence of VH 31 …”

The sodium‐glucose cotransporter‐2 inhibitor canagliflozin does not increase risk of non‐genital skin and soft tissue infections in people with type 2 diabetes mellitus: A pooled post hoc analysis from the CANVAS Program and CREDENCE randomized double‐blind trials

“…Similarly, an English primary care cohort of 85 312 participants with type 1 or type 2 diabetes mellitus found glycaemic control was independently associated with risk of hospitalization for infection 42 . Another study used two‐sample Mendelian randomization in the genome‐wide association study of 171 322 participants and found a causal relationship between obesity and SSTI 43 . Previous studies have also found associations between insulin requirement and risk of infection 44 .…”

“…42 Another study used two-sample Mendelian randomization in the genome-wide association study of 171 322 participants and found a causal relationship between obesity and SSTI. 43 Previous studies have also found associations between insulin requirement and risk of infection. 44 Insulin is not a first-line therapy for type 2 diabetes mellitus and is generally initiated after failure of first-line therapies or if firstline therapies are contraindicated (such as in advanced chronic kidney disease).…”

The causal effect of oxidative stress on the risk of glaucoma

“…The I 2 statistic, Cochran's Q statistic for the MR-IVW method, and Rucker's Q statistic for the MR-Egger method were used to determine the heterogeneity of the MR analysis, with I 2 < 50 % or P > 0.05 indicating no heterogeneity [ 28 ]. Finally, leave-one-out analysis was used to examine the influence of individual SNPs on the IVW estimates [ 29 , 30 ].…”