Influence of Age

Several studies have reported that adipose tissue distribution changes with age. Increasing age has been consistently associated with increased visceral adipose tissue deposition in both sexes [1,2]. This section will briefly review the scientific evidence available on this topic.

Several studies have also documented age-related changes in adipose tissue distribution as reflected by an increase in the waist-to-hip ratio, which has been used as an anthropometric index of relative abdominal adiposity [3,4]. In a sample of 52,953 women, it was found that the body weight increase observed with age was more likely to accumulate in the abdominal area than the gluteo-femoral area [3]. In the 1,179 participants of the Baltimore Longitudinal Study of Aging, a waist-to-hip ratio increase was reported across various age groups (from 17 to 96 years of age) in both men and women [5]. In women, the onset of menopause accelerated abdominal fat accumulation. In another sample of Dutch volunteers (men and women), age was found to be a strong correlate of selective abdominal adipose tissue accumulation as estimated by increased waist circumference [6].

In young individuals (men and women) and middle-aged women, excess energy is preferentially stored in subcutaneous fat depots, although visceral adipose stores may also increase [1] selectively in some genetically susceptible individuals [7]. In this regard, the ratio of abdominal subcutaneous to visceral adipose tissue has been shown to be markedly higher in women than in men and to decrease with age in both sexes. In another study, age was again positively correlated to visceral adiposity and negatively correlated with the amount of abdominal subcutaneous adipose tissue [8]. DeNino et al. [9] have even estimated that in non-obese women, visceral adipose tissue increases with age at a rate of 2.36 cm² per year.

Increased visceral adipose tissue deposition with age is particularly significant among men and post-menopausal women who, on average, have more than twice the amount of visceral adipose tissue than pre-menopausal women [2]. Figure 1 shows the significant increase of visceral adiposity in association with the whole body fat distribution changes with age in men and women. However, even in middle-aged pre-menopausal women, it has been shown that visceral adipose tissue deposition was higher when compared to young women, suggesting that age was associated with an increase in abdominal adiposity in women even before the onset of menopause [10].

In young pre-menopausal women, age-related changes in visceral adipose tissue relative to total body fat have been reported to be greater than the increase in total body fat over a 4-year follow-up period, and this phenomenon was found to be independent of race (Figure 2) [11]. This study also reported that the age-related increase in total adiposity was greater in African-American women than in white women. However, visceral adiposity was greater in white women at baseline, increased with age, and remained higher in white than in black women.

In a 7-year follow-up study of pre-menopausal women, a 30% increase in visceral adiposity was reported although total adiposity indices did not change (Figure 3) [12]. Over the same period, waist circumference, waist-to-hip ratio, and visceral adipose tissue area measured by computed tomography were all significantly increased. In addition, the increase in waist circumference over the 7-year follow-up predicted the increase in visceral adiposity. This latter finding suggest that monitoring changes in waist circumference over time could be useful in clinical practice to detect changes in visceral adiposity with years. This study provides evidence that clinicians should look beyond body weight measurements and the body mass index in order to properly assess whether patients are accumulating dangerous visceral fat over time.