WHAT ARE THE PATHOLOGIES ASSOCIATED WITH OBESITY?
Obesity, on its own and depending on the type of distribution (a greater incidence if the distribution is visceral) and the grade of obesity, it is often associated with the presence of other chronic illnesses (comorbidities) that provoke clinical necessity and great economic burden, as well as possible mortality in those affected individuals.
Diabetes Mellitus
There are many studies that link excess in weight with an increase in Type 2 Diabetes Mellitus, obesity being the most important risk factor in its development. Obesity causes a resistance to insulin levels in the blood because of increase in secretion by the pancreas; even though there is an increase of insulin, it is not enough to normalize the glucose levels in the blood.
Lowering weight improves the number of glycaemia and optimises the behavior of insulin. Many times these changes happen with a moderate loss of weight varying between 5 and 10%.
Dyslipemia
Obese people, secondary to the state of resistance to insulin and an increase in insulin levels in the blood, tend to present with diverse lipid alterations: elevation in concentrations of total cholesterol, LDL cholesterol (popularly called “bad" cholesterol), and triglycerides, and lower values in HDL cholesterol (known as “good or protector" cholesterol). In addition, the LDL cholesterol modifies into smaller and denser structures. This profile is associated with an elevated level in cardiovascular risk, facilitating arterogenesis (fat deposits in the artery that provoke a decrease in gauge).
La disminución de peso tiende a producir normalización de los parámetros alterados, descendiendo los triglicéridos y el colesterol LDL, y aumentando el colesterol HDL.
Arterial Hypertension
Obesity constitutes as much risk factor for this illness as it does for its progression. Therefore, arterial hypertension is 2.5 times more frequent in patients with obesity as in individuals at a normal weight; at the same time, approximately 50% of patients with hypertension are obese. However, the prevalence of arterial hypertension in obesity varies with age, sex and race.
Risk of hypertension depends on distribution of body fat, being greater in those with a high level of abdominal fat. However, the mechanisms that cause an increase in blood pressure in obese patients are still not completely understood.
Some studies have shown that weight loss is as effective as a diet low in salt. Therefore, every kilogram of weight lost constitutes a reduction of 0.3-1 mmHg of blood pressure. Maintained obesity not only increases the levels blood pressure, it can also create a worse response to antihypertensive pharmaceuticals making it more difficult to control.
Cardiovascular Diseases; Cerebrovascular Accidents And Alterations In The Veins
Obesity constitutes risk factors for cardiovascular diseases (angina, heart attacks, cardiac insufficiencies, hypertrophic myocardium) and the other associated risk factors like hypertension, diabetes, and an increase in LDL cholesterol or a decrease in HDL cholesterol must be added as well. Another important factor is the topographic distribution of the fat, considering the cardiovascular risk factors are higher when it is predominantly visceral (abdominal).
It has been observed that an increase in BMI (greater or equal to 27 Kg/m2) and weight gain after the age of 18 is associated with an increased risk in cerebrovascular diseases.
In patients with obesity there are changes in the return venous circulation as well as lymphatic circulation, producing oedemas and varicose syndrome, most frequently in women with gynecoid obesity. The risk of profound venous thrombosis increases with the weight of the individual, but is not related to the type of distribution of fat.
Hyperurecimia
Obesity is related to an increase in uric acid and this, in time, can provoke attacks of gout. It seems to be directly related to elevation of insulin levels.
Respiratory Alterations
Obesity can produce changes in pulmonary function. In general, obese patients (because of higher levels of fat contained in the thoracic wall) mobilize their lungs less, thus producing decreased volume and pulmonary circulation. The most significant pulmonary problem caused by obesity is Obstructive Sleep Apnea Syndrome (OSAS).
OSAS appears in 25-40% of individuals with morbid obesity and in 10% of grave obesity. It is more frequent in men and post-menopausal women. An individual with OSAS exhibits daytime sleepiness, morning cephalous, changes in character and irritability, a decrease in work performance, broken sleep, snoring and apneas (respiratory pauses). Its diagnosis is confirmed through a polysomnography under strict criteria, also establishing a diagnosis of the gravity of the ailment.
OSAS also worsens quality of life of the patient and can produce, when it has developed, respiratory insufficiencies, arterial hypertension and cardiac insufficiency.
To improve symptoms losing weight is fundamental, but many times, due to the gravity of the illness, the use of a nocturnal ventilator mask (BIPAP) is necessary and, in some cases, a surgical treatment of the larynx is useful.
Articular And Osseous Alterations
An excess of weight provokes changes to the skeletal system as the osteoarticular system is not designed to support large levels of extra weight. Obesity provokes a constant erosion of articulation that rapidly degenerates and finally results in arthrosis, mostly in the knees, hips, ankles, and spine occurring overall in women with gynecoidal obesity. The frequency of arthrosis in articulations that do not support weight, like the hands, is also increased. In growing-aged children obesity can produce deformities.
A small loss in weight in individuals with normal or high weight levels lowers the risk of developing arthrosis in the knees by 20-50%. Once arthrosis has developed, weight-loss also improves symptoms.
In obese individuals the osseous mass is increased, without knowing the exact cause, and decreases with weight-loss. In this way it can be said that obesity protects against osteoporosis.
Alterations In The Digestive System
Cholelithiasis (biliary gallstones) is a condition of the hepatic-biliary system that is more frequent in obese patients, especially in females. The increased risk is in relation to the rise in hepatic production of cholesterol and the elimination of rich bile in cholesterol discharge, larger in size and less mobility of the gall bladder. Rapid weight-loss (more than 1.5Kg/week) can facilitate the formation of gallstones that can provoke biliary colic, and for that reason moderate and progressive weight-loss is recommended.
Hepatic steatosis (fatty liver) is the accumulation of fat in the interior of liver cells. It is a benign illness that does not tend to progress towards hepatic cirrhosis. It is clearly related to obesity, diabetes and hypercholesterolemia. It does not cause symptoms, and is reflected only in hepatic function blood tests by a light rise in transaminase. It is resolved with proper weight-loss, except in those patients that produce this loss through various bariatric surgery techniques (a frequent cause of fatty liver).
A greater prevalence of gastrooesophageal reflux has not been demonstrated with obesity, but an improvement of symptoms has been shown through moderate weight loss.
Oncological Alterations
Obesity is associated with a greater mortality rate from prostate and colon and rectal cancer in males, while in females (especially in post-menopausal) mortality rates increase in cases of the uterine, ovarian, endometrial, breast and biliary tract cancer. Prostate cancer in obese subjects is more benign, has less determined growth and frequency of metastasis, in individuals without obesity.
Dermatological Alterations
The appearance of coetaneous stretch marks is frequent and reflects the tension in the skin caused by subcutaneous fat deposits. Hirsurtism (an increase in hair growth in women in normally masculine areas) occurs in greater frequency in women with abdominal obesity because of an increase in the production of testosterone. Acanthosis Nigricans is associated with and increase in the resistance to insulin and hyperinsulinemia and is characterized by hyper pigmentation in the neck, armpit, elbows and surfaces of extension in the limbs.
Endocrine Alterations, Reproduction And Pregnancy
There are numerous endocrine alterations and affect the entire endocrine system. Subjects with obesity can show an alteration in the metabolism of cortisol (with an effect on the accumulation of fat).
In males with morbid obesity the production of testosterone by the testicles can be reduced. Obese females show elevated levels of testosterone, producing one of the most common gynaecological alterations associated with obesity, called chronic anovulation syndrome or polycystic ovarian syndrome (POS). Obese women with POS show a greater prevalence of menstrual changes, anovulation, difficulty in gestation and a greater incidence of abortions. Weight-loss can provoke a reduction in the resistance to insulin, a characteristic of this syndrome, with an improvement of symptoms and of the parameters of reproductive function and pregnancy.
Obesity during pregnancy constitutes risk factors for the development of gestational diabetes and arterial hypertension, urinary tract infections, cholelithiasis and vascular complications like venous thrombosis. In addition, an elevated BMI before gestation is associated with a greater frequency of macrosomia (a larger than normal foetus, more than 4.0 Kg). Due to the elevated incidence of macrosomia and the increase of fat tissue in the pelvis, vaginal birth can be difficult and are usually done by means of caesarean.
Psychological And Psychiatric Alterations
There is no evidence of a greater frequency of psychiatric disorders, for example depression, in obese individuals, but alterations have been observed in social behaviour in relation to an excess in weight (shyness, isolation, timidity) and derived problems from these limitations.
Increase In Mortality
A decrease in life expectancy because of premature death, especially in young adults, as a consequence of obesity has been documented in recent years. The most recent studies have determined that obesity produces the same risk of premature mortality as smoking. Thus, evaluating the probability of death before reaching the age of 70:
1. Overweight women who do not smoke have a reduction in life expectancy of 3.3 years.
2. Overweight men who do not smoke have a reduction of 3.1 years.
3. Obese women who do not smoke have a reduction of 7.1 years.
4. Obese men who do not smoke have a reduction of 5.8 years.
5. Obese women who smoke have an expectative reduction of 7.2 years with respect to women who smoke and have normal weight.
6. Obese men who smoke, with respect to smokers at a normal weight have a reduced expectancy of 6.7 years.
7. Obese women who smoke have a reduction ion life expectancy of 13.3 years with respect to non-smoker at a normal weight.
8. Obese male smokers have a reduction of 13.7 years with respect to non-smokers at a normal weight.