Obesity is a medical condition associated with excess adipose tissue that inevitably leads to health complications like diabetes, hypertension, heart disease, and other chronic illnesses. Adipose tissue serves not only as a storage for triacylglycerols, but also as an endocrine organ that releases numerous chemical messengers (adipokines) communicating and affecting other tissues in the body.
Biochemical causes of obesity include:
-Increased intake of simple carbohydrates and fats. Consumption of fast food, junk food, processed instead of homemade foods high in sugar but lacking nutrients result in the development of obesity.
-Cushing’s syndrome. Patients with this syndrome take corticosteroids that increase blood sugar levels, increased cortisol levels result in fat accumulation in different parts of the body. This condition is also associated with visceral obesity that is hard to differentiate from simple obesity. Low dose dexamethasone suppression test is used to differentiate Cushing’s syndrome from obesity.
– Prader-Willi syndrome (PWS). As a result of this syndrome, hyperphagia and obesity are usually developed. The initial stage of PWS is poor feeding and failure to thrive. Mechanisms of obesity development in patients with PWS are: impaired hypothalamic pathways of satiety control which results in hyperphagia, aberration in hormones regulating food intake, reduced energy expenditure due to hypotonia and altered behavior with features of autism spectrum disorder. Later in life when profound muscular hypotonia is developed, patients with PWS struggle staying physically active, which reduces muscle movements and , therefore, energy expenditure (2).
-Misbalance of energy intake and energy usage. Diets high in calories combined with sedentary lifestyle result in excessive accumulation of fat tissue in the body and the development of obesity.
-Hypothyroidism. Though slight decrease in energy expenditure contributes to weight gain, hypothyroidism is an uncommon cause of obesity. Water retention which is reversible once thyroid hormone treatment is started is what actually contributes to weight gain in patients with hypothyroidism.
Other factors that can result in obesity include lack of exercising, genetics, and environmental (no access to healthy foods, advertisement that encourages purchasing fast food).
Excess weight tends to diminish almost every aspect of health, increasing the risk of various debilitating and deadly diseases.
Metabolic. Impaired metabolism results in insulin resistance, type 2 diabetes, dyslipidemia, hypertension and premature heart disease. The dyslipidaemia that develops in obese patients includes elevated triglycerides, higher levels of low density lipoprotein (LDL) particles and decreased high density lipoprotein (HDL) levels and these changes are all known to be atherogenic (3).
Endocrine. Several endocrine impairments are associated with obesity. Hypothyroidism and Cushing’s syndrome mentioned above, growth hormone (GH) and testosterone deficiency, polycystic ovarian syndrome, hypothalamic lesions, and genetic syndromes often can be seen in patients suffering from obesity (3).
Musculoskeletal. Obesity is linked to gouty arthritis as well as osteoarthritis. Recently it was discovered that obesity is also associated with rheumatoid arthritis. Besides that, obesity is a risk factor in the onset and progression of disorders of the hip, knee, ankle, foot and shoulder (3).
Respiratory. Hypoventilation common for obesity leads to complex interactions involving changes in the ventilatory mechanics and anomalies in breathing control. COPD and sleep apnea-hypopnea syndrome (SAHS) that are often present in obese patients are triggered and aggravated by obesity (3).
Reproductive. Obesity influences different aspects of reproductive system – from libido to the ability to conceive. During pregnancy, obese women are at higher risk of gestational diabetes, preeclampsia, early and late miscarriage, and complications during labor and delivery. Also, their children have higher chances of having congenital anomalies (3).