bottleneckblooz said:
Not necessarily. There are lots of guys that have gynecomastia that have never taken anabolic androgenic steroids.
The prevalence of gynecomastia varies according to age and definition. During three phases of male life (neonatal, puberty, and aging), breast enlargement can be regarded as a physiological rather than a pathological event. Breast tissue was palpable in more than 90% of 282 newborns with no difference between the sexes. The time in gestation when breast tissue becomes palpable varies greatly. It was found in some infants younger than 32 weeks gestation but was not palpable in 33% of newborns of 36 weeks gestation [7]. In healthy term infants, the diameter of the breast may increase during the first weeks of life, only to decrease later. Complete regression is usual toward the end of the first year of life.
Gynecomastia is a normal occurrence during puberty. Breast tissue larger than 0.5 cm was palpated in 39% of 1,865 boys aged 10 to 16 years [1]. Palpable breast tissue was found among 49% of 377 adolescents aged 10 to 15 years [8]. Gynecomastia prominent enough to be detected in general surveys of sexual development is noted in less than 10% of adolescent boys [9,10].
In boys with pubertal gynecomastia, the glandular tissue is usually less than 4 cm in diameter and resembles the early stages of female breast budding. Pubertal gynecomastia has a peak incidence of nearly 65% at age 14 years. It follows the appearance of male sexual development by at least 6 months [11]. The enlargement of adolescent male breast tissue is often unilateral, asymmetric, and painful.
Pubertal gynecomastia disappears spontaneously in approximately 75% of boys within 2 years and in approximately 90% of boys within 3 years [1,8,11]. However, a recent evaluation of 954 healthy young men aged 18 to 26 years has found more than 2 cm breast tissue in 40.5%, raising the possibility of a lower regression rate than previously reported [12].
An uncommon but important variant of pubertal gynecomastia is pubertal macrogynecomastia. This term refers to breast enlargement similar to that of the middle and late stages of normal female breast development. The glandular tissue extends 5 cm or more in diameter [11]. This condition is idiopathic in 75% of the cases, but boys with pubertal macrogynecomastia were found to be taller and heavier than average [13].
Several studies have emphasized that breast enlargement may be detected in high-prevalence (close to 40%) of normal adult men [2,12]. A study of 214 hospitalized adult men revealed that up to 65% of the subjects had palpable gynecomastia (at least 2 cm), with the greatest prevalence found in the group aged 50 to 69 years [3]. In most subjects with gynecomastia, the diameter of the breast tissue was less than 5 cm and breast enlargement was bilateral [2,3,12]. There are no racial differences in the prevalence of gynecomastia [1,10].
It is difficult to estimate the true prevalence of gynecomastia among adults. The distinction between true enlargement of breast tissue and lipomastia is difficult, especially in overweight men. The incidence of gynecomastia of recent onset was less than 10% in three large unselected autopsy series. Gynecomastia was reported to be most common in the young and the elderly [6,14,15]. Unfortunately, no correlation regarding clinically palpable breast tissue in life was provided in these autopsy-based studies.
Pathogenesis and Etiology
Disturbed androgen-to-estrogen ratio has been suggested as the pathogenic mechanism for gynecomastia [16,17]. Pathologic states causing gynecomastia can be divided into conditions of increased estrogen production or decreased androgen formation or action. Drugs and idiopathic causes are responsible for many cases of gynecomastia.
The three physiologic peaks of gynecomastia fit well with the concept of imbalances in the androgen-to-estrogen ratio. Neonatal gynecomastia is attributed to circulating estrogens produced by the maternal-placental-fetal unit acting on the neonatal breast. A significant increase of serum estradiol levels was observed with the onset of gynecomastia in pubertal boys, whereas serum testosterone levels did not change; thus, the testosterone-to-estradiol ratio decreased [26]. Throughout puberty, ratios of androstenedione to estrone (E1) and estradiol (E2) ratios were significantly lower in boys with gynecomastia than in the control group [27]. The free serum testosterone level was significantly lower and the testosterone–estrogen-binding globulin level was significantly higher in boys with gynecomastia in comparison with boys who had no signs of gynecomastia [8]. Local formation of estrogen within the breast may also play a role in the gynecomastia of puberty [28].
Although most older men still have serum testosterone levels within the range considered to be normal for young men, they were found to have a decrease in total serum testosterone, decreased levels of free testosterone, and increase of testosterone-binding globulin. The net result of these changes leads to a decrease in the ratio of androgen to estrogen [29]. Aging is also associated with increased body fat mass and specific aromatase activity in adipose tissue [30,31]. Such changes in elderly men may result in an appearance of gynecomastia in the absence of other diseases.