title: Ethnic variation in the activity of lipid desaturases and their relationships with cardiovascular risk factors in control women and an at-risk group with previous gestational diabetes mellitus: a cross-sectional study.
abstract: BACKGROUND
  Lipid desaturase enzymes mediate the metabolism of fatty acids to long chain polyunsaturated fatty acids and their activities are related to metabolic risk factors for Type 2 diabetes (T2DM) and coronary heart disease (CHD). There are marked ethnic differences in risks of CHD and T2DM but little is known about ethnic differences in desaturase activities.
  
  
  METHODS
  Samples from a study of CVD risk in women with previous gestational diabetes were analysed for percentage fatty acids in plasma free fatty acid, triglyceride, cholesterol ester and phospholipid pools for 89 white European, 53 African Caribbean and 56 Asian Indian women. The fatty acid desaturase activities, stearoyl-CoA desaturase (SCD, calculated separately for C16 and C18 fatty acids), delta 6 desaturase (D6D) and delta 5 desaturase (D5D) were estimated from precursor-to-product ratios and their relationships with adiposity, blood pressure, cholesterol, triglycerides, HDL cholesterol and insulin sensitivity explored. Ethnic differences in desaturase activities independent of ethnic variation in risk factor correlates of desaturase activities were then identified.
  
  
  RESULTS
  There was significant ethnic variation in age, BMI, waist circumference, blood pressure, serum triglycerides and HDL cholesterol concentrations and insulin resistance. Desaturase activities showed significant correlations, independent of ethnicity, with BMI, waist circumference, triglycerides and HDL cholesterol. Independent of ethnic variation in BMI, waist circumference, triglycerides and HDL cholesterol, SCD-16 activity, calculated from each of the four lipid pools measured, was 18-35 percent higher in white Europeans than in African Caribbeans or Asian Indians (all p < 0.001). Similar, though less consistent differences were apparent for SCD-18 activity. Also independently of risk factor variation, but specifically when calculated from the cholesterol ester and phospholipid, pools, D6D activity was significantly lower in Asian Indians, and D5D activity higher in African Caribbeans.
  
  
  CONCLUSIONS
  Significant ethnic differences exist in desaturase activities, independently of ethnic variation in other risk factors. These characteristics did not accord with higher risk of T2DM among African Caribbeans and Asian Indians nor with lower risk of CHD among African Caribbeans but did accord with the higher risk of CHD in Asian Indians.
authors.affiliation: Diabetes Endocrinology and Metabolic Medicine, Faculty of Medicine, Imperial College London, St. Mary's Campus, Room G1, Norfolk Place, London W2 1PG, UK.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Gray
authors.forename: Eleni
authors.initials: E
authors.lastname: Kousta
authors.forename: Mark I
authors.initials: MI
authors.lastname: McCarthy
authors.forename: Ian F
authors.initials: IF
authors.lastname: Godsland
authors.forename: Soundarajan
authors.initials: S
authors.lastname: Venkatesan
authors.forename: Victor
authors.initials: V
authors.lastname: Anyaoku
authors.forename: Desmond G
authors.initials: DG
authors.lastname: Johnston
mesh_terms: D000328:Adult; D001794:Blood Pressure; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000201:enzymology* / Q000208:ethnology / Q000473:pathology; D002788:Cholesterol Esters / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D000090943:Delta-5 Fatty Acid Desaturase; D003924:Diabetes Mellitus, Type 2 / Q000201:enzymology* / Q000208:ethnology / Q000473:pathology; D016640:Diabetes, Gestational / Q000201:enzymology* / Q000208:ethnology / Q000473:pathology; D005006:Ethnicity; D044943:Fatty Acid Desaturases / Q000097:blood*; D005227:Fatty Acids / Q000097:blood; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000097:blood; D050602:Linoleoyl-CoA Desaturase / Q000097:blood*; D011247:Pregnancy; D012307:Risk Factors; D013230:Stearoyl-CoA Desaturase / Q000097:blood*; D014280:Triglycerides / Q000097:blood; D006113:United Kingdom / Q000453:epidemiology; D055105:Waist Circumference
chemical_list: D002788:Cholesterol Esters; D008076:Cholesterol, HDL; D000090943:Delta-5 Fatty Acid Desaturase; D005227:Fatty Acids; D007527:Isoenzymes; D014280:Triglycerides; D044943:Fatty Acid Desaturases; D013230:Stearoyl-CoA Desaturase; D050602:Linoleoyl-CoA Desaturase