Leptin : a risk marker for cardiovascular disease

• Main Author: Söderberg, Stefan
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Umeå universitet, Medicin 1999
• Subjects: leptin; testosterone; dysfibrinolysis; hyperinsulinemia; insulin resistance syndrome; menopause; cardiovascular disease; MONICA; epidemiology; Clinical Medicine; Klinisk medicin; Northern Sweden
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-101355

A major cause of morbidity and early death in the Western societies is cardiovascular disease (CVD) secondary to atherosclerotic disease. Metabolic aberrations have been linked to CVD. Particular combinations of these so-called risk markers are common and (central) obesity, Type 2 diabetes, impaired glucose tolerance, hypertension, dyslipidemia, dysfibrinolysis and hyperinsulinemia are often associated. This has been entitled the Insulin Resistance Syndrome (1RS), due to underlying insulin resistance. Moreover, aberrations in circulating levels of androgens and IGF-binding proteins are associated with 1RS. The main hypothesis in this thesis was that increased levels of leptin, the recently discovered adipocyte derived hormone in combination with obesity may be an important factor in the link between 1RS and the development of CVD. The association between leptin levels and variables associated with the Insulin Resistance Syndrome was studied in a healthy sample (n=163) of middle-aged men and women from the northern Sweden MONICA health survey. Central obesity was associated with high levels of leptin and insulin in men and women. In contrast, central obesity was linked to low testosterone levels in men, whereas in women, central obesity was associated with high testosterone but low SHBG levels. Furthermore, in males and postmenopausal women central obesity was a major determinant for circulating leptin. Leptin levels were associated with biochemical androgenicity in non-obese men and women. The direction of this association was dependent on gender and body fat distribution. Specifically, testosterone was inversely associated to leptin in non-obese men and in normal weight women whereas testosterone was positively associated to leptin in non-obese women. In contrast, adiposity and insulin levels, but not testosterone, were associated to leptin in obese men and women. Similarly, leptin was associated to IGFBP-1 and proinsulin in non-obese men and premenopausal women. Hyperleptinemia was significantly associated to ...