Human Reproduction, Vol. 19, No. 1, 215,
January 2004
© 2004 European Society of Human Reproduction and Embryology
Are serum adiponectin levels really reduced in obese women with polycystic ovary syndrome?
1 Department of Molecular and Clinical Endocrinology & Oncology, University ‘Federico II’ of Naples, Naples and 2 Department of Obstetrics & Gynecology, University ‘Magna Graecia’ of Catanzaro, Catanzaro, Italy
3 To whom correspondence should be addressed. e-mail: francescoorio{at}virgilio.it
Dear Sir,
We read with interest the paper by Panidis et al. (2003)
reporting reduced serum adiponectin levels in women with polycystic ovary syndrome (PCOS) and would like to comment on some of the methodological and clinical aspects of the study.
The authors selected 85 women and classified them as: group I, 35 subjects with PCOS and a body mass index (BMI) >25 kg/m2; group II, 35 subjects with PCOS and a BMI <25 kg/m2; and group III, 15 healthy women without PCOS with a BMI <25 kg/m2. We feel that the paper by Panidis et al. (2003) appears to be methodologically weak, and that the data are not consistent enough for the lack of a control group that includes obese subjects without PCOS. In fact, to demonstrate a clear reduction of serum adiponectin levels in obese (or ‘overweight’, see above) PCOS we think that it should have been necessary to compare two groups of obese BMI-matched women with and without PCOS.
Panidis et al. confirm our previous data (Orio et al., 2003) regarding the negative correlation between serum adiponectin and BMI. Furthermore, conversely to our findings (Orio et al., 2003), they state that serum adiponectin levels are reduced in obese women with PCOS. We retain that this statement is incorrect, chiefly for the fact that their obese PCOS group was wrongly defined as BMI >25 kg/m2. The ‘obese PCOS group’ studied by Panidis et al. had a BMI (kg/m2 ± SD) of 32.5 ± 6.1, and therefore also included a high percentage of overweight PCOS women.
In humans, serum adiponectin levels have been found to be paradoxically decreased in obese compared with normal-weight individuals (Arita et al., 1999). Furthermore, we previously reported fasting serum adiponectin levels in patients with PCOS comparable to those observed in control women matched for age and BMI (Orio et al., 2003). In addition, obese PCOS women also exhibited reduced adiponectin levels compared with normal-weight women with PCOS, and adiponectin levels were inversely correlated with BMI both in PCOS and healthy women (Orio et al., 2003).
Although in their introduction Panidis et al. (2003) stated that adiponectin might be a link between obesity and insulin resistance, they showed that adiponectin levels did not correlate with either insulin levels or the glucose/insulin ratio, indeces of insulin resistance (Legro et al., 1998).
Recently, Ducluzeau et al. (2003) found a close relationship between low adiponectin levels and glucose disposal rate, confirming that adiponectin levels are decreased in insulin-resistant states (Weyer et al., 2001), and showed that glucose disposal correlated negatively with BMI and fasting insulin levels (Ducluzeau et al., 2003). Ducluzeau et al. (2003) concluded that adiponectin level is a good indicator of abdominal fat mass and is associated with insulin resistance, conversely to the results of Panidis et al. (2003).
After all these considerations we feel that the relationship between adiponectin and PCOS is more complex than the paper by Panidis et al. (2003) suggests; however, we agree with their conclusion that adiponectin does not seem to be actively involved in the pathogenesis of PCOS, although it might play a role in the complicated metabolic abnormalities of the syndrome.
References
Arita Y, Kihara S, Ouchi N, Takahashi M, Maeda K and Miyagawa J (1999) Paradoxical decrease of an adipose specific protein, adiponectin, in obesity. Biochem Biophys Res Commun 257,79–83.[CrossRef][Web of Science][Medline]
Ducluzeau PH, Cousin P, Malvoisin E, Bornet H, Vidal H, Laville M and Pugeat M (2003) Glucose-to-insulin ratio rather than sex hormone-binding globulin and adiponectin levels is the best predictor of insulin resistance in nonobese women with polycystic ovary syndrome. J Clin Endocrinol Metab 88,3626–3631.
Legro RS, Finegood D and Dunaif A (1998) A fasting glucose to insulin ratio is a useful measure of insulin sensitivity in women with polycystic ovary syndrome. J Clin Endocrinol Metab 83,2694–2698.
Orio F Jr, Palomba S, Cascella T, Milan G, Mioni R, Pagano C, Zullo F, Colao A, Lombardi G and Vettor R (2003) Adiponectin levels in women with polycystic ovary sindrome. J Clin Endocrinol Metab 88,2619–2623.
Panidis D, Kourtis A, Farmakiotis D, Mouslech T, Rousso D and Koliakos G (2003) Serum adiponectin levels in women with polycystic ovary syndrome. Hum Reprod 18,1790–1796.
Weyer C, Funahashi T, Tanaka S, Hotta K, Matsuzawa Y, Pratley RE and Tateranni A (2001) Hypoadiponectinemia in obesity and type 2 diabetes: close association with insulin resistance and hyperinsulinemia. J Clin Endocrinol Metab 86,1930–1935.
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