Bárbara Guerra-Carvalho, Marco G. Alves, Pedro F. Oliveira. Obesity and Male Infertility: An Overview. Int J Diabetol Vasc Dis Res. 2022;8(1e):1-3. 1 OPEN ACCESS https://scidoc.org/IJDVR.php International Journal of Diabetology & Vascular Disease Research (IJDVR) ISSN 2328-353X *Corresponding Author: Pedro F. Oliveira, LAQV-REQUIMTE and Department of Chemistry, University of Aveiro, Aveiro, Portugal. E-mail: pfobox@gmail.com Received: March 26, 2022 Published: March 28, 2022 Citation: Bárbara Guerra-Carvalho, Marco G. Alves, Pedro F. Oliveira. Obesity and Male Infertility: An Overview. Int J Diabetol Vasc Dis Res. 2022;8(1e):1-3. Copyright: Pedro F. Oliveira © 2022. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribu- tion and reproduction in any medium, provided the original author and source are credited. Obesity and Male Infertility: An Overview Editorial Bárbara Guerra-Carvalho 1,2,3,4 , Marco G. Alves 1,2,5,6 , Pedro F. Oliveira 3* 1 Department of Anatomy and UMIB - Unit for Multidisciplinary Research in Biomedicine, ICBAS - School of Medicine and Biomedical Sciences, University of Porto, Porto, Portugal. 2 Laboratory for Integrative and Translational Research in Population Health (ITR), University of Porto, Porto, Portugal. 3 LAQV-REQUIMTE and Department of Chemistry, University of Aveiro, Aveiro, Portugal. 4 Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal. 5 Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, ES-17003 Girona, Spain. 6 Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona, ES-17003 Girona, Spain. Obesity has reached pandemic proportions in recent decades. In 2016, the World Health Organization estimated that over 1.9 bil- lion adults were overweight (39 percent of the world’s adult popu- lation) and more than 650 million were obese [1]. These numbers are expected to rise with up to 3.3 billion individuals being over- weight or obese by 2030 [2]. Obesity and overweight are both de- scribed as an excessive or abnormal accumulation of body fat that is harmful to one’s health and are clinically defned based on the body mass index (BMI). BMI≥30 kg/m 2 or ≥25 Kg/m 2 is often used to categorize obesity and overweight in adults, respectively [1]. Nevertheless, this index should only be used as a reference because it does not take into account body fat distribution nor the percentage of lean and fat body mass [3]. Obesity, which was once thought to be an issue only in high-in- come countries, is now dramatically increasing in low and mid- dle-income countries, impacting adults and children of all ages, regardless of their ethnicity or socioeconomic background. The increased consumption of high-calorie diets, rich in saturated fats and sugars, and sedentary lifestyle habits are two major factors contributing to the increase in the prevalence of obesity. Obesity is a major risk factor for several pathologies, such as cardiovascu- lar diseases, type 2 diabetes mellitus, musculoskeletal disorders, accelerated aging, several cancers, poor mental health, among other disorders [4]. Obesity is also linked to metabolic syndrome, as increased waist circumference, increased triglyceride levels, glucose intolerance, low high-density lipoprotein cholesterol, and hypertension constitute the fve factors included in the diagnostic criteria for metabolic syndrome [5]. Infertility has arisen as one important, but often overlooked, co- morbidity of obesity. Studies highlight that obesity-related male infertility is induced by immune, hormonal, and metabolic dys- functions, mostly caused by excessive adipose tissue. These fac- tors have been shown to disrupt the male reproductive potential, particularly through alterations in the hypothalamic-pituitary-go- nadal (HPG) axis, impairment of testicular steroidogenesis, and dysregulation of testicular metabolism [6, 7]. In men, obesity has also been linked to erectile dysfunction, abnormal semen param- eters, as well as poor pregnancy and ART outcomes [9]. Changes in sperm parameters have been linked to obesity and overweight. Obese and overweight men had a higher risk of oli- gozoospermia and azoospermia than men of normal weight, ac- cording to Sermondade et al [9]. Ma et al. observed similar results, implying that a greater BMI was associated with a decrease in sperm volume, sperm count, and sperm motility [10]. Chavarro et al. also identifed a correlation between increased BMI and lower ejaculate volume, but no link between sperm concentration, sperm motility, or sperm morphology and BMI [11]. An increase in BMI was also associated with an increase in the number of sperm with abnormal morphology [12]. In contrast, a study by Pauli et al. found no association between BMI and sperm parame- ters [13]. Despite some studies have been done to link obesity and overweight to sperm parameters, the mechanisms by which obe- sity causes poor sperm parameters are still not fully understood. HPG axis dysregulation and hormonal alterations, particularly the decrease in intratubular testosterone concentration, are thought to play a major role in the decrease of sperm quality. Increased infammation and oxidative stress in the testis, as well as increased testicular temperature, due to adipose tissue accumulation in the suprapubic and scrotal area, may also contribute to poor sperm parameters associated with obesity and overweight [7]. Obesity-induced infertility and subfertility are mediated primarily through dysregulation of the HPG axis, which results partially