What Are the Physical Characteristics Associated with a Normal Metabolic Profile Despite a High Level of Obesity in Postmenopausal Women?1

Abstract

Although obesity is often associated with insulin resistance and a cluster of metabolic disturbances, the existence of a subgroup of healthy but obese individuals has been postulated. It is unclear why some obese individuals fail to show traditional risk factors associated with the insulin resistance syndrome despite having a very high accumulation of body fat. To address this issue, we identified and studied a subgroup of metabolically normal but obese (MNO) postmenopausal women to gain insight into potential physiological factors that may protect them against the development of obesity-related comorbidities. We carefully examined the metabolic characteristics of 43 obese, sedentary postmenopausal women (mean +/- SD, 58.0 +/- 6.0 yr). Subjects were classified as MNO or as metabolically abnormal obese (MAO) based on an accepted cut-point for insulin sensitivity (measured by the hyperinsulinemic/euglycemic clamp technique). Thereafter, we determined 1) body composition (fat mass and lean body mass), 2) body fat distribution (abdominal visceral and sc adipose tissue areas, midthigh sc adipose tissue and muscle attenuation), 3) plasma lipid-lipoprotein levels, 4) plasma glucose and insulin concentrations, 5) resting blood pressure, 6) peak oxygen consumption, 7) physical activity energy expenditure, and 8) age-related onset of obesity with a questionnaire as potential modulators of differences in the risk profile. We identified 17 MNO subjects who displayed high insulin sensitivity (11.2 +/- 2.6 mg/min.kg lean body mass) and 26 MAO subjects with lower insulin sensitivity (5.7 +/- 1.1 mg/min.kg lean body mass). Despite comparable total body fatness between groups (45.2 +/- 5.3% vs. 44.8 +/- 6.6%; P: = NS), MNO individuals had 49% less visceral adipose tissue than MAO subjects (141 +/- 53 vs. 211 +/- 85 cm(2); P: < 0.01). No difference was noted between groups for abdominal sc adipose tissue (453 +/- 126 vs. 442 +/- 144 cm(2); P: = NS), total fat mass (38.1 +/- 10.6 vs. 40.0 +/- 11.8 kg), muscle attenuation (42.2 +/- 2.6 vs. 43.6 +/- 4.8 Houndsfield units), and physical activity energy expenditure (1060 +/- 323 vs. 1045 +/- 331 Cal/day). MNO subjects had lower fasting plasma glucose and insulin concentrations and lower insulin levels during the oral glucose tolerance test (P: values ranging between 0.01-0.001). No difference was observed between groups for 2-h glucose levels and glucose area during the oral glucose tolerance test. MNO subjects showed lower plasma triglycerides and higher high density lipoprotein cholesterol concentrations than MAO individuals (P: < 0.01 in both cases). Results from the questionnaire indicated that 48% of the MNO women presented an early onset of obesity (<20 yr old) compared with 29% of the MAO subjects (P: = 0.09). Stepwise regression analysis showed that visceral adipose tissue and the age-related onset of obesity explained 22% and 13%, respectively, of the variance observed in insulin sensitivity (total r(2) = 0.35; P: < 0.05 in both cases). Our results support the existence of a s...

Influence of segmental body composition and adiposity hormones on resting metabolic rate and substrate utilization in overweight and obese adults

“…Thigh muscle size has previously been shown to be negatively associated with mortality risk in both normal weight and overweight elderly populations (66–96 years) [28]. In men, muscle mass, specifically in the lower limbs, was inversely associated with visceral fat [27], but more research on the relationship between LM and metabolic function in women is needed [22,19]. …”

<p>Lifetime predictors of stroke in subjects without a diagnosis of hypertension: the aerobics center longitudinal study</p>

“…Although the mechanisms underlying this metabolic profile are not yet clear, it has been suggested that the number of years that an individual has been obese, the person’s metabolic activity, and the distribution and histological characteristics of adipose tissue play a more important role than the amount of adipose tissue in determining metabolic health among obese individuals 48,49. Moreover, studies have reported that individuals with MHO have lower levels of C-reactive protein,50 higher levels of insulin,51 better CRF levels, and better general physical fitness than obese individuals with metabolic syndrome 52. Finally, scientific evidence supports the idea that individuals with MHO have less sedentary behavior time and higher levels of CRF than individuals with metabolically unhealthy obesity 53.…”

Тhe prevalence of metabolically healthy obesity: data from the epidemiological survey in of Novosibirsk

“…В настоящее время этот феномен известен под названием «metabolically healthy obesity», «метаболически здоровое ожирение» (МЗО) или также его называют «парадокс ожирения», «метаболически здоровое состояние у лиц с ожирением», «неполный метаболический синдром» [3]. Несмотря на наличие избыточного веса или ожирения, у данной когорты пациентов можно наблюдать благоприятный метаболический профиль, характеризующийся сохраненной инсулиночувствительностью, отсутствием АГ, нормальным липидным, гормональным профилем, отсутствием воспаления и неизмененными печеночными ферментами [4][5][6][7]. В настоящее время неизвестны индивидуальные факторы и механизмы, лежащие в основе протективного профиля МЗО.…”