Article 30: Obesity, Hyperlipidemia, Gallstones, and Sexual Dysfunction

Hyperlipidemia is defined as a condition in which the concentrations of blood lipid components such as cholesterol, triglycerides, and total lipids exceed normal levels. The characteristics of lipid metabolism in obese individuals include elevated levels of free fatty acids in the plasma, and generally elevated levels of blood lipid components such as cholesterol, triglycerides, and total lipids. In obese individuals, 55.8% have plasma cholesterol levels above 5.2 mmol/L.

In men over 60 and women over 50, plasma cholesterol levels rise significantly. Obese patients often have hyperinsulinemia, leading to excessive triglyceride synthesis, and therefore frequently present with hyperlipidemia, especially hypertriglyceridemia.

In addition, due to the reduced number of insulin receptors in fat, muscle, liver cells, etc., patients are less sensitive to insulin, often resulting in decreased glucose tolerance and increased cholesterol, triglycerides, and free fatty acids. Therefore, they are prone to diseases such as atherosclerosis, coronary heart disease, diabetes, and gallstones.

50% of obese individuals have fatty infiltration in the liver, due to increased adipose tissue and the increased release of free fatty acids. Weight loss can reduce fatty infiltration. Fatty liver after hepatitis is often caused by obesity resulting from overeating and insufficient physical activity.

It is commonly seen in the recovery phase of acute hepatitis and in patients with chronic active hepatitis who are HBsAg positive and have elevated alanine aminotransferase (ALT). This is a result of inappropriately increasing nutrition and reducing physical activity.

Obese individuals often have a preference for high-sugar diets. As large amounts of sugar enter the liver, exceeding the liver's capacity to store glycogen, a significant portion of the sugar is metabolized into acetyl-CoA, leading to increased fatty acid synthesis. Obese individuals often also have impaired glucose tolerance and hyperinsulinemia, prompting the liver to synthesize large amounts of triglycerides, resulting in endogenous hyperlipidemia.

The characteristics of fat metabolism in obese individuals are: elevated concentrations of free fatty acids in plasma, and generally increased levels of blood lipid components such as cholesterol, triglycerides, and total lipids, indicating disordered fat metabolism. Obese individuals have reduced utilization of free fatty acids, leading to their accumulation in blood lipids and increased blood lipid volume.

Patients with hypertriglyceridemia caused by carbohydrates are prone to obesity. When these patients consume more carbohydrates, their plasma triglyceride levels rise; conversely, when they reduce their carbohydrate intake, their hyperlipidemia may improve or even disappear.

Similarly, weight loss can also lower plasma triglyceride levels to normal in these patients. Therefore, for obese individuals, controlling their diet and losing weight can promote a decrease in blood lipid levels, which is of great significance in preventing atherosclerosis and coronary heart disease.

Gallstones are stones that originate in the gallbladder and bile duct system, and often coexist with cholecystitis. The two conditions promote each other, creating a vicious cycle that causes the stones to grow continuously and lead to complications.

Gallstone formation is related to factors such as increased cholesterol concentration in bile, impaired gallbladder emptying, and infection. Under normal circumstances, cholesterol, bile salts, and phospholipids in bile maintain a certain ratio, keeping cholesterol in a supersaturated dissolved state.

When the cholesterol concentration in bile increases and the composition of bile changes, cholesterol in the bile will precipitate out. Under certain conditions (such as increased mucus secretion from the gallbladder mucosa and impaired gallbladder emptying), gallstones with cholesterol as the main component will form.

The incidence of gallstones is indeed higher among obese individuals than among the general population. When a person's weight exceeds 50% of their ideal body weight, the incidence of symptomatic gallstones can increase sixfold!

In mild cases, there may be no symptoms. In more severe cases, symptoms may include loss of appetite, discomfort or even pain in the upper right abdomen, which is significantly aggravated after eating fatty foods. When gallstones obstruct the bile duct or gallbladder opening, it can cause acute cholecystitis, causing severe abdominal pain that radiates to the right side of the lower abdomen. This pain may be accompanied by vomiting, fever, and can even be life-threatening.

Most patients with gallstones are obese. This is because obese individuals often have excess nutrition and high blood lipids, leading to increased bile secretion to digest fats, thus increasing the burden on the gallbladder. Simultaneously, significantly elevated cholesterol levels greatly increase the chance of cholesterol stones forming in the gallbladder. Furthermore, reduced physical activity in obese individuals may also contribute to gallstone formation.

According to reports, a survey of 574 middle-aged and elderly intellectuals found that 325 were underweight or of normal weight, while 249 were overweight or obese. Among them, 31 cases had gallstones, with only 3 cases in the normal weight group and 28 cases in the overweight/obese group. This indicates that the incidence of gallstones is significantly higher in the overweight/obese group than in the normal weight group.

In general, the incidence of gallstones is higher in obese individuals, although the underlying mechanisms are not fully understood. Additionally, many patients with cholecystitis are also more obese than the general population.

Because obese people have higher cholesterol levels in their blood, the bile secreted by the liver will inevitably contain more cholesterol. Once the cholesterol concentration in the bile reaches a certain level, cholesterol will precipitate out.

In middle-aged and elderly individuals, the elastic fibers in the gallbladder and bile ducts proliferate, the gallbladder wall thickens, and elasticity decreases, leading to difficulty in gallbladder emptying, bile stasis, increased viscosity, and the formation of stones. Once stones form, bile excretion is obstructed, and the mechanical irritation of the gallbladder wall by the stones easily leads to infection and cholecystitis.

Obese individuals have a significantly higher risk of developing gallstones than those of normal weight. Obese men are twice as likely to develop gallstones as those of normal weight, while obese women are three times more likely. Clinical studies have found that 30% of obese individuals are diagnosed with gallstones during surgery, compared to only 5% of non-obese individuals. Obese individuals who wish to reduce their risk of gallstones should limit their intake of high-cholesterol foods and strive to lose weight.

Excessive body fat, in both men and women, can lead to a noticeable decline in sexual function. This is because sex hormones are transported to various organs via the bloodstream; if too much accumulates in adipose tissue, it can cause a decline in sexual function.

In obese men, increased body fat leads to a greater conversion of androgens into estrogens, with blood concentrations more than doubling. Higher estrogen levels can inhibit pituitary gonadotropin secretion, thereby reducing testosterone secretion from the testes.

Because obese men have increased estrogen and decreased androgen, their masculinity is weakened and their effeminate qualities are enhanced, leading to varying degrees of decreased sexual function. Severe obesity manifests as decreased sexual function in areas such as erection, intercourse, ejaculation, and orgasm.

Furthermore, a high-fat diet can lower testosterone levels in men, leading to decreased sexual function or even sexual dysfunction. After effective weight loss, this "reversal" of estrogen and androgen levels can be reversed, resulting in some improvement or even complete recovery of sexual function.

Obesity has a significant impact on ovarian function, manifesting as abnormal follicle development, ovulation disorders, and poor ovulation. These changes can significantly affect the menstrual cycle and fertility.

Obese girls often experience early menarche. Some have suggested a correlation between menarche and weight, indicating that menstruation begins when a girl reaches a certain weight during growth and development. The average weight of a girl at menarche is 40-42 kg. Another perspective on early menarche in obese girls is due to increased adipose tissue and higher estrogen levels, which directly stimulate menstruation.

Statistics show that among obese women, 16.4% experience amenorrhea, 28.7% experience oligomenorrhea, 5.5% experience irregular menstruation, and 5.5% experience menorrhagia or hypermenorrhea, with a total abnormality rate as high as 56.1%.

The main cause of sexual dysfunction in obese women is decreased secretion of gonadotropins. A woman's libido largely depends on her androgen levels; obese women generally have low libido, which is closely related to their low androgen levels.

Menopause is the stage in which endocrine changes are most significant in women, during which the secretion of estrogen and progesterone from the ovaries decreases or even ceases. Obese women experience menopause earlier, with menopause ending sooner.

Cataracts are one of the most common eye diseases among the elderly and a significant cause of blindness. In the United States, cataracts have become the third leading cause of disability among the elderly. The causes of cataracts are numerous and complex.

Recently, medical experts from Harvard Medical School and Righam Women's Hospital in Boston have found that overweight middle-aged and elderly people are more prone to cataracts.

Researchers conducted a follow-up study from 1982 to 1988 on 17,700 doctors aged 40 to 84. By analyzing differences in age, weight, smoking habits, vitamin intake, and other factors considered to influence cataract formation, they found that 34% of cataracts were attributed to being overweight, 12% to smoking, 4% to hypertension, and 2% to diabetes. This demonstrates a close relationship between obesity and cataracts.

Gout is a disease caused by long-term purine metabolism disorder, resulting in elevated uric acid levels in the blood and tissue damage. Gout often occurs in obese people who are overnourished, and gout attacks often occur after a large meal.

Although gout and obesity are two completely different diseases, they are closely related. The clinical features of gout include hyperuricemia, recurrent acute arthritis attacks, tophi formation, joint deformities, renal parenchymal damage, and renal uric acid stones.

Purines are breakdown products of nucleoproteins and mainly come from protein-rich foods such as lean meat and animal organs. Therefore, some people believe that limiting purine-rich foods can control gout attacks, seemingly unrelated to obesity.

However, clinical observations show that gout occurs more frequently in obese patients, with an incidence rate about 50% higher than in other groups. Maintaining or achieving an ideal weight significantly reduces the incidence of gout in obese patients, possibly due to abnormal lipid metabolism caused by obesity.

Some believe that obese patients often consume high-protein, low-fat, and low-sugar foods to control their weight, which increases endogenous purine sources and can trigger gout attacks. Therefore, obese patients with a history of gout should strictly control their weight, but avoid high-protein foods. While restricting calories, they can appropriately increase the proportion of complex carbohydrates and adopt a purine-limiting, low-calorie, low-fat, and low-sugar diet.

A study measuring blood uric acid levels in 494 participants over 50 years of age found that obese individuals had a three times higher prevalence of hyperuricemia than non-obese individuals. The higher the degree of obesity, the higher the blood uric acid level, and the higher the prevalence of gout.

Some reports indicate that approximately 9.2% of people who are less than 20% overweight have hyperuricemia; about 9.4% are overweight between 20% and 40%; and up to 20% are overweight or over 40%. Controlling the intake of purine-rich foods, limiting food intake, and losing weight can lower blood uric acid levels and reduce the frequency of gout attacks.

Childhood obesity increases the risk of spondylolisthesis, most commonly affecting preschool children. The cause is the replacement of the growth layer of the epiphyseal cartilage with fibrous tissue, leading to weakness in this area. Endocrine disorders are also a contributing factor, with many obese children of school age also experiencing genital hypoplasia, resulting in an imbalance of growth hormone and sex hormones.

The most common musculoskeletal disease among obese middle-aged and elderly people is joint deformity. Lower limb joint deformities are significantly affected by body weight. This is because obesity itself increases weight, placing a long-term excessive load on the musculoskeletal system, especially the lower limbs, which are prone to osteoarthritis and often experience lower back and leg pain.

Because lower back and leg pain affects the mobility of obese patients, it is extremely detrimental to those trying to lose weight. However, the lower back and leg pain symptoms of obese patients generally lessen or even disappear as their weight decreases. Knee joint deformities are more common in short, stout middle-aged and elderly women. Obese individuals often have diabetes, which can lead to neuropathy and also cause bone and joint abnormalities.