Central fat accumulation in women with polycystic ovary syndrome evaluated by different methods

Daniela Barros, post graduate student of the Surgical Clinic Program at Ribeirão Preto Medical School, University of São Paulo (FMRP-USP), Ribeirão Preto, SP, Brasil.

The study Dual-energy X-ray absorptiometry and adiposity index are sensitive methods to evaluate central fat accumulation in women with polycystic ovary syndrome and normal body mass index aimed to determine the differences in body fat distribution and central obesity indicators using dual-energy X-ray absorptiometry (DXA), adiposity indices, and anthropometric indices between women with and without polycystic ovary syndrome (PCOS). A multicentric team from Faculdade de Medicina de Ribeirão Preto, Instituto Federal de São Paulo (campus Jacareí), and Centro de Pesquisa e Desenvolvimento de Medicamentos, Universidade Federal do Ceará, used clinical and laboratory examination history, including transvaginal ultrasound, fasting blood samples, anthropometric measurements, and DXA scans to evaluate 179 women with PCOS (PCOS group) and 100 without PCOS (non-PCOS group).

The volunteers were grouped by body mass index (BMI): normal (18-24.9 kg/m²), overweight (25-29.9 kg/m²), or obese (>30 kg/m²). The visceral adiposity index (VAI) and lipid accumulation product (LAP) were calculated, regions of interest (ROIs) were determined, and the fat mass index (FMI) was calculated using DXA. VAI, LAP, ROIs, FMI, and adiposity indices by DXA were higher in women with PCOS and a normal BMI. In both PCOS and non-PCOS groups, the ROIs progressively increased from normal BMI to overweight and obese, and from overweight to obese. Obese women with PCOS showed high trunk fat mass.

However, obesity was not able to modify these trunk/periphery fat ratios in PCOS from overweight to higher BMI. These variables were associated with the incidence of PCOS. The authors concluded that in women with PCOS and normal BMI, both DXA and the adiposity indices, VAI, and LAP, are more sensitive methods to evaluate total body fat and fat accumulation in the central abdominal region. It was also observed that as BMI increased, the differences in measurements between women with and without PCOS decreased (KOGURE, G.S., et al.).

PCOS is a common endocrine disorder in women of reproductive age, with an estimated prevalence of 6%-20% (LIZNEVA, D., et al.). The prevalence of obesity in PCOS is reportedly 30%-70% (ROMANO, L.G.M., et al.). However, a small proportion of patients present with a normal body mass index (BMI; ≤25 kg/m²) which can minimize the adverse effects of syndrome-related hormonal and metabolic profiles, except IR (TOOSY, S., et al.).

Central obesity plays an important role in PCOS development and is associated with metabolic disturbances and IR, regardless of normal BMI, overweight, or obesity (LUOTOLA, K., et al.; CARMINA, E., et al.). Considering the importance of evaluating central obesity and its relationship with metabolic disorders and CVD risk, it is necessary to document BMI and estimate central obesity to better stratify the risk of PCOS in women. That is the main reason that this observational and retrospective study aimed to determine the differences in body fat distribution and central obesity indicators using DXA, adiposity, and anthropometric indices between BMI-matched women with and without PCOS, as well as in the metabolic and hormonal features of the disorder (KOGURE, G. S., et al.).

The markers of whole-BFM and central obesity are important for estimating abdominal adiposity to better stratify the risk of PCOS in women. Kogure, et al., observed that women with PCOS showed increased Total FM and fat accumulation in the central region compared to women without PCOS matched by BMI (KOGURE, G.S., et al.).

Image: iStock.

This difference appears to be more pronounced in women with normal BMI in both DXA and adiposity index. Carmina, et al. observed an increase in the amount of central abdominal fat in PCOS patients, but not in total and trunk fat. Moreover, only women who presented with increased central abdominal fat had higher insulin and androgen levels and reduced insulin sensitivity (CARMINA, E., et al.). Satyaraddi, et al. observed that TotalFM and TrunkFM were higher in PCOS women than in non-PCOS controls matched by BMI.

Moreover, PCOS patients with and without obesity had increased visceral adiposity, with a difference even after correcting for body weight. Additionally, the IR was more prevalent in obese PCOS patients (80%) than in non-obese individuals (20%), as well as hyperandrogenism, either biochemical or clinical, 60% and 30%, respectively (SATYARADDI, A., et al.). The results of the present trial support these findings (KOGURE, G.S., et al.).

A higher BMI in PCOS is associated with VAI and LAP obesity indices (RIBEIRO, V.B., et al.; DURMIS, U., et al.; DE MEDEIROS, S.F., et al.). In the present study, LAP and VAI showed worse scores from normal BMI to obese women with PCOS, and the same curve of these indices was observed in women without PCOS. However, VAI was not different in women with PCOS from overweight to obese and in women without PCOS from lean to overweight. Although the explanations for this need to be clarified, it is likely that the changes associated with triglycerides may be reflected in the VAI (KOGURE, G.S., et al.).

For overweight/obese women with PCOS, anthropometric indices, such as BMI and waist-to-height ratio (WHtR), are more effective in predicting IR (HUANG, X., et al.). However, a recent study demonstrated the superiority of VAI in predicting metabolic syndrome and RI in women with PCOS with BMI < 30 and BMI ≥ 30 over other anthropometric parameters or anthropometric-metabolic indices (DE MEDEIROS, S.F., et al.).

Among the anthropometric indices mentioned previously, BMI stands out. BMI lacks discriminatory power between fat and lean tissues for a standardized definition of obesity (GALLAGHER, D., et al.), i.e., there was no linear association with body fat percentage (WILDMAR, R.P.). Although several women with PCOS have a normal body fat level based on BMI, the present results from Kogure et al (KOGURE, G.S., et al.). corroborate those of a previous study (ROJAS, J., et al.) and demonstrate that most women with PCOS and normal BMI have an excess body fat level.

The strength of this study was that PCOS patients were carefully characterized for clinical trials. Moreover, the groups evaluated were paired for BMI, thus reducing the confounding effects of this variable. Although we collected details on sedentary lifestyle in the PCOS and non-PCOS groups, this study was limited by the retrospective nature of a convenience sample. Detailed studies clearly defining body composition by assessing visceral, subcutaneous, central, and peripheral fat mass may provide more reliable information on the evolution of body fat distribution following BMI and phenotypes (KOGURE, G.S., et al.).

The findings from the present study aid in understanding the complexity of PCOS, demonstrating the distribution of body fat, and hormonal and metabolic profiles of women matched by BMI. The use of viable methods, such as VAI and LAP, to estimate central obesity, especially in thin women, can assist in clinical practice (KOGURE, G.S., et al.).

References

CARMINA, E., et al. Abdominal fat quantity and distribution in women with polycystic ovary syndrome and extent of its relation to insulin resistance. J Clin Endocrinol Metab [online]. 2007, vol. 92, no. 7, pp. 2500-2505 [viewed 20 September 2023]. https://doi.org/10.1210/jc.2006-2725. Available from: https://pubmed.ncbi.nlm.nih.gov/17405838/

DE MEDEIROS, S.F., et al. The Role of Visceral Adiposity Index as Predictor of Metabolic Syndrome in Obese and Nonobese Women with Polycystic Ovary Syndrome. Metab Syndr Relat Disord [online]. 2021, vol. 19, no. 1, pp. 18-25 [viewed 20 September 2023]. https://doi.org/10.1089/met2020.0045. Available from: https://pubmed.ncbi.nlm.nih.gov/32845813/

DURMIS, U., et al. Visceral adiposity index levels in overweight and/or obese, and non-obese patients with polycystic ovary syndrome and its relationship with metabolic and inflammatory parameters. J Endocrinol Invest [online]. 2017, vol. 40, no. 5, pp. 487-497 [viewed 20 September 2023]. https://doi.org/10.1007/s40618-016-0582-x. Available from: https://pubmed.ncbi.nlm.nih.gov/27838846/

GALLAGHER, D., et al. Healthy percentage body fat ranges: An approach for developing guidelines based on body mass index. Am J Clin Nutr [online]. 2000, vol. 72, no. 3, pp. 694-701 [viewed 20 September 2023]. https://doi.org/10.1093/ajcn/72.3.694. Available from: https://pubmed.ncbi.nlm.nih.gov/10966886/

HUANG, X., et al. Body fat indices as effective predictors of insulin resistance in obese/non-obese polycystic ovary syndrome women in the Southwest of China. Endocrine [online]. 2019, vol. 65, no. 1, pp. 81-85 [viewed 20 September 2023]. https://doi.org/10.1007/s12020-019-01912-1. Available from: https://pubmed.ncbi.nlm.nih.gov/30924083/

LIZNEVA, D., et al. Criteria, prevalence, and phenotypes of polycystic ovary syndrome. Fertil Steril [online]. 2016, vol. 106, no. 1, pp. 6-15 [viewed 20 September 2023]. https://doi.org/10.1016/j.fertnstert.2016.05.003. Available from: https://pubmed.ncbi.nlm.nih.gov/27233760/

LUOTOLA, K., et al. Testosterone is associated with insulin resistance index independently of adiposity in women with polycystic ovary syndrome. Gynecol Endocrinol [online]. 2018, vol. 34, no. 1, pp. 40-44 [viewed 20 September 2023]. https://doi.org/10.1080/09513590.2017.1342793. Available from: https://pubmed.ncbi.nlm.nih.gov/28678568/

RIBEIRO, V.B., et al. Association of measures of central fat accumulation indices with body fat distribution and metabolic, hormonal, and inflammatory parameters in women with polycystic ovary syndrome. Arch Endocrinol Metab [online]. 2019, vol. 63, no. 4, pp. 417-426 [viewed 20 September 2023]. https://doi.org/10.20945/2359-3997000000157. Available from: https://pubmed.ncbi.nlm.nih.gov/31365630/

ROJAS, J., et al. Polycystic Ovary Syndrome, Insulin Resistance, and Obesity: Navigating the Pathophysiologic Labyrinth. Int J Reprod Med [online]. 2014, vol. 2014, pp. 719050 [viewed 20 September 2023]. https://doi.org/10.1155/2014/719050. Available from: https://pubmed.ncbi.nlm.nih.gov/25763405/

ROMANO, L.G.M., et al. Anormalidades metabólicas em mulheres com síndrome dos ovários policísticos: obesas e não obesas. Rev Bras Ginecol Obstet [online]. 2011, vol. 33, no. 6, pp. 310-316 [viewed 20 September 2023]. https://doi.org/10.1590/S0100-72032011000600008. Available from: https://www.scielo.br/j/rbgo/a/gP3tBs3YssTBtJyJtMB9RCd/

SATYARADDI, A., et al. Body composition, metabolic characteristics, and insulin resistance in obese and nonobese women with polycystic ovary syndrome. J Hum Reprod Sci [online]. 2019, vol. 12, no. 2, pp. 78 [viewed 20 September 2023]. https://doi.org/10.4103/jhrs.JHRS_2_19. Available from: https://pubmed.ncbi.nlm.nih.gov/31293320/

TOOSY, S., et al. Lean polycystic ovary syndrome (PCOS): an evidence-based practical approach. J Diabetes Metab Disord [online]. 2018, vol. 1, no. 2, pp. 277-285 [viewed 20 September 2023]. https://doi.org/10.1007/s40200-018-0371-5. Available from: https://pubmed.ncbi.nlm.nih.gov/30918863/

WILDMAR, R.P. The Obese Without Cardiometabolic Risk Factor Clustering and the Normal Weight With Cardiometabolic Risk Factor Clustering. Arch Intern Med [online]. 2008, vol. 168, no. 15, pp. 1617-124 [viewed 20 September 2023]. https://doi.org/10.1001/archinte.168.15.1617. Available from: https://pubmed.ncbi.nlm.nih.gov/18695075/

To read the article, access

KOGURE, G.S., et al. Dual-energy X-ray absorptiometry and adiposity index are sensitive methods to evaluate central fat accumulation in women with polycystic ovary syndrome and normal body mass index. Arch. Endocrinol. Metab. [online]. 2023, vol. 67, no. 5, e000627 [viewed 20 September 2023]. https://doi.org/10.20945/2359-3997000000627. Available from: https://www.scielo.br/j/aem/a/mCsL5nfSPzbMkW5pQsKxwZc/

External links

Archives of Endocrinology and Metabolism – AEM: https://www.scielo.br/aem

Gislaine Satyko Kogure – Orcid: https://orcid.org/0000-0002-2860-846X