Obesity : Classification, Risk Factor, Diagnosis, Treatment, and Drug

Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health.It can be defined as having a body mass index (BMI) of 30 or more.Body mass index (BMI) is a measurement that takes a person's weight and height into account.BMI is usually expressed in kilograms for square metre, resulting when weight is measured in kilograms and height in metres.Obesity is commonly caused by a combination of excessive food intake, lack of physical activity, and genetic susceptibility.BMI is defined as the subject's weight divided by the square of their height and is calculated as follows :

Where m and h are the subject's weight and height respectively


The Classification of Obesity

• Under weight   : 18.5 kg/m2
• Normal weight : from 18.5 kg/m2 up to 25.0 kg/m2
• Over weight      : from 25.0 kg/m2 up to 30.0 kg/m2
• Class I obesity  : from 30.0 kg/m2 up to 35.0 kg/m2
• Class II obesity (Severe obesity) : from 35.0 kg/m2 up to 40.0 kg/m2
• Class III obesity (Morbid obesity) : 40.0 kg/ m2
• Super obesity   : 45.0 kg/m2 up to 50.0 kg/m2

Ten possible contributors to the recent increase of obesity :

1. Insufficient sleep.
2. Endocrine disruptors is environtmental pollutants that interfere with lipid metabolism.
3. Decreased variability in ambient temperature.
4. Decreased rates of smoking. Smoking suppresses appetite.
5. Increased use of medications that can cause weight gain (Atypical antipsychotics).
6. Porpotional increases in ethnic and age groups that tend to heavier.
7. Pregnacy at later age which may cause susceptibility to obesity in children.
8. Epigenetic risk factors.
9. Natural selection for higher body mass index.
10. Assortative mating leading to increase concentration of obesity risk factors

Risk factors of obesity

1. Genetics
2. Sedentary lifestyle
3. Psychological factors
4. Environment and community
5. Certain medications, including thiazolidinediones, steroids, certain antidepressants, insulin, sulfonylureas, atypical antipsychotics, certain anticonvulsants ( phenytoin and valproate ), pizotifen, and some of hormonal contraceptive.
6. Medical illness increases obesity risk include genetic syndrome, some congenital or acquired conditions, such as Cushing's syndrome, hypothyroidism, growth hormone deficiency, and the eating disorders (binge eating disorder and night eating syndrome).

Complications of Obesity

• Cardiovascular disease
• Asthma
• Diabetes mellitus type 2
• Obstructive sleep apnea
• Osteoarthritis
• Certain types of cancer, such as colon, endrometrial, breast
• Stroke
• High blood pressure
• Heart disease
• Infertility
• High cholesterol

Diagnosis

Obesity is diagnosed by certain tests :

• Accurate measures of body fat and body fat distribution include skinfold thickness, waist-to-hip comparisons.
• Screening tests, such as ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) scans.
• Blood tests are to examine cholesterol and glucose levels.
• Liver function tests.
• Diabetes screen.
• Thyroid tests.
• Heart tests, such as an electrocardiogram.

The Treatment of Obesity

1. Dieting and physical exercise
2. Lifestyle and behaviour changes.
3. Certain prescription weight loss medications
4. Weight loss surgery (Bariatric Surgery) is not a quick fix.It is a major surgery that can have serious risk.Surgical options include :

• Gastric by pass surgery creates a small pouch at the top of the stomach that connects directly to the small intestine.Food and liquids go through the pouch and into the intestine by passing most of the stomach.
• Laparoscopic Adjustable Gastric Banding (LAGB) separates the stomach into two pouches using a band.
• Gastric Sleeve removes part of the stomach.
• Biliopancreatic Diversion with duodenal switch removes most of the stomach.

Drugs for Obesity

• Orlistat (Xenical) 
• Lorcaserin (Belviq)
• A combination of Phentermine and Topiramate (Qsymia)

Weight loss with Orlistat is modest, an average of 2.9 kilograms (6.4 lb) at 1 to 4 years.It's use has side effectd that are associated with high rates of gastrointestinal and kidney.

Lorcaserin results an average of 3.1 kilograms weight loss (3% of body weight).The side effect of lorcaserin can increase heart valve problems.

Prevention of Obesity

• Doing Physical activities or exercises, such as walking, biking, and swimming for twenty or thirty minutes daily.
• Eating high fat, high calorie foods in moderation.
• Consuming nutrious foods like fruits, vegetables, lean protein, and whole grains.
• Consuming dietary fiber.