title: Racial Disparity in the Associations of Cotinine with Insulin Secretion: Data from the National Health and Nutrition Examination Survey, 2007-2012.
abstract: BACKGROUND
  Although relationships between smoking/high cotinine and type 2 diabetes have consistently been observed, few studies have investigated the relationship between cotinine and underlying pathophysiological defects that characterize diabetes aetiology. This study aimed to test the associations between cotinine and measures of insulin resistance or insulin secretion.
  
  
  METHODS
  This analysis included 5,751 non-diabetic adult American from the National Health and Nutrition Examination Survey (NHANES) from 2007-2012. Insulin function was represented with two indexes: insulin resistance index (HOMA-IR) and insulin secretion index (HOMA-B) estimated by homeostasis model assessment. We categorized cotinine levels into quartiles and estimated the odds of HOMA-IR in the 4th quartile and HOMA-B in the 1st quartile among cotinine categories using multiple logistic regression models.
  
  
  RESULTS
  Cotinine concentration was not associated with the risk of high HOMA-IR. Association of cotinine with low HOMA-B existed and differed by race/ethnicity (P for interaction<0.05). High cotinine concentration (in the 4th quartile) was associated with an increased risk of low HOMA-B compared with low cotinine concentrations(1st -2nd quartiles) among white (odds ratio[OR], 1.51 [95% confidence interval[CI], 1.16-1.97]) or black participants (OR, 2.98 [95%CI, 1.90-4.69]) but not among Mexican (OR, 1.79 [95%CI, 0.90-3.53]) or other Hispanic(OR, 1.02 [95%CI, 0.56-1.86]) participants. Such associations remained significant even after further adjustment for HOMA-IR.
  
  
  CONCLUSIONS
  High cotinine is associated with decreased insulin secretion function only in white and black non-diabetic U.S. adult population. Results evaluating cotinine in ethnically homogeneous populations may not be broadly generalizable to other racial/ethnic groups.
authors.affiliation: Department of Epidemiology, Beijing Anzhen Hospital, Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Diseases, Beijing, China.
authors.forename: Rong
authors.identifier: http://orcid.org/0000-0001-9674-0561
authors.initials: R
authors.lastname: Liu
authors.affiliation: Department of Neurobiology, Beijing Institute of Geriatrics, Beijing Xuan Wu Hospital, Capital Medical University, Beijing, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Zheng
authors.affiliation: Beijing An Zhen Hospital, Capital Medical University, The Key Laboratory of Remodeling-related Cardiovascular Diseases, Ministry of Education, Beijing Institute of Heart, Lung and Blood Vessel Diseases, Beijing, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Du
authors.affiliation: Mary Ann and J. Milburn Smith Child Health Research Program, Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America.
authors.forename: Katherine Kaufer
authors.initials: KK
authors.lastname: Christoffel
authors.affiliation: Mary Ann and J. Milburn Smith Child Health Research Program, Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America.|Key Laboratory of Genomic and Precision Medicine, China Gastrointestinal Cancer Research Center, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China.|Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America.|University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
mesh_terms: D000328:Adult; D044383:Black People / Q000706:statistics & numerical data; D003367:Cotinine / Q000009:adverse effects / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000208:ethnology* / Q000209:etiology / Q000378:metabolism; D005260:Female; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance; D000078790:Insulin Secretion; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D014481:United States / Q000208:ethnology; D044465:White People / Q000706:statistics & numerical data; D001741:Black or African American
chemical_list: D007328:Insulin; D003367:Cotinine