title: Higher leptin levels in Asian Indians than Creoles and Europids: a potential explanation for increased metabolic risk.
abstract: OBJECTIVE
  Leptin predicts cardiovascular diseases and type 2 diabetes, diseases to which Asian Indians are highly susceptible. As a risk marker, leptin's intra-individual and seasonal stability is unstudied and only small studies have compared leptin levels in Asian Indians with other populations. The aim of this study was to explore ethnicity related differences in leptin levels and its intra-individual and seasonal stability.
  
  
  METHODS
  Leptin and anthropometric data from the northern Sweden MONICA (3513 Europids) and the Mauritius Non-communicable Disease (2480 Asian Indians and Creoles) studies were used. In both studies men and women, 25- to 74-year old, participated in both an initial population survey and a follow-up after 5-13 years. For the analysis of seasonal leptin variation, a subset of 1780 participants, 30- to 60-year old, in the Västerbotten Intervention Project was used.
  
  
  RESULTS
  Asian Indian men and women had higher levels of leptin, leptin per body mass index (BMI) unit (leptin/BMI) or per cm in waist circumference (WC; leptin/waist) than Creoles and Europids when adjusted for BMI (all P<0.0005) or WC (all P<0.005). In men, Creoles had higher leptin, leptin/BMI and leptin/waist than Europids when adjusted for BMI or WC (all P<0.0005). In women, Creoles had higher leptin/BMI and leptin/waist than Europids only when adjusted for WC (P<0.0005). Asian Indian ethnicity in both sexes, and Creole ethnicity in men, was independently associated with high leptin levels. The intra-class correlation for leptin was similar (0.6-0.7), independently of sex, ethnicity or follow-up time. No seasonal variation in leptin levels was seen.
  
  
  CONCLUSIONS
  Asian Indians have higher levels of leptin, leptin/BMI and leptin/waist than Creoles and Europids. Leptin has a high intra-individual stability and seasonal leptin variation does not appear to explain the ethnic differences observed here.
authors.affiliation: The Research and Development Unit, Jämtland County Council, Ostersund, Sweden. mikael.lilja@jll.se
authors.forename: M
authors.initials: M
authors.lastname: Lilja
authors.forename: O
authors.initials: O
authors.lastname: Rolandsson
authors.forename: J E
authors.initials: JE
authors.lastname: Shaw
authors.forename: V
authors.initials: V
authors.lastname: Pauvaday
authors.forename: A J
authors.initials: AJ
authors.lastname: Cameron
authors.forename: J
authors.initials: J
authors.lastname: Tuomilehto
authors.forename: K G M M
authors.initials: KG
authors.lastname: Alberti
authors.forename: P Z
authors.initials: PZ
authors.lastname: Zimmet
authors.forename: S
authors.initials: S
authors.lastname: Söderberg
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People; D001786:Blood Glucose / Q000378:metabolism*; D001823:Body Composition / Q000502:physiology; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000097:blood / Q000453:epidemiology / Q000208:ethnology*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000453:epidemiology / Q000208:ethnology*; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D020738:Leptin / Q000097:blood*; D008297:Male; D008436:Mauritius / Q000453:epidemiology; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000453:epidemiology / Q000208:ethnology*; D012307:Risk Factors; D012621:Seasons; D012737:Sex Factors; D013548:Sweden / Q000453:epidemiology; D055105:Waist Circumference
chemical_list: D001786:Blood Glucose; D020738:Leptin