Obesity: A Chronic Low-Grade Inflammation and Its Markers

Abstract

As the prevalence of obesity continues to rise, the world is facing a major public health concern. Obesity is a complex disease associated with an increase in several inflammatory markers, leading to chronic low-grade inflammation. Of multifactorial etiology, it is often used as a measurement of morbidity and mortality. There remains much unknown regarding the association between obesity and inflammation. This review seeks to compile scientific literature on obesity and its associated inflammatory markers in chronic disease and further discusses the role of adipose tissue, macrophages, B-cells, T-cells, fatty acids, amino acids, adipokines, and hormones in obesity. Data were obtained using PubMed and Google Scholar. Obesity, inflammation, immune cells, hormones, fatty acids, and others were search words used to acquire relevant articles. Studies suggest brown adipose tissue is negatively associated with body mass index (BMI) and body fat percentage. Researchers also found the adipose tissue of lean individuals predominantly secretes anti-inflammatory markers, while in obese individuals more pro-inflammatory markers are secreted. Many studies found that adipose tissue in obese individuals showed a shift in immune cells from anti-inflammatory M2 macrophages to pro-inflammatory M1 macrophages, which was also correlated with insulin resistance. Obese individuals generally present with higher levels of hormones such as leptin, visfatin, and resistin. With obesity on the rise globally, it is predicted that severe obesity will become most common amongst low-income adults, black individuals, and women by 2030, making the need for intervention urgent. Further investigation into the association between obesity and inflammation is required to understand the mechanism behind this disease.

Keywords: adipokine; adipose tissue; browning of white adipose tissue; fatty acid; inflammatory processes/inflammatory markers; nutrition and metabolism .obesity. dietary fiber; obesity and inflammatory markers; obesity: an immune disease; prevalence of obesity; role of hormones in obesity.

Figure 1. Prevalence of obesity in the United States (2017-2018) among adults aged 20 and over, organized by age and sex

Adapted from: NCHS, National Health and Nutrition Examination Survey, 2017–2018 [34]

Figure 2. Age-adjusted obesity and severe obesity prevalence trends in the United States over a 10-year period (2007-2008 to 2017-2018) among adults aged 20 and over

Adapted from: NCHS, National Health and Nutrition Examination Survey, 2017–2018 [34]