title: Self-reported alcohol intake is a better estimate of 5-year change in blood pressure than biochemical markers in low resource settings: the PURE study.
abstract: BACKGROUND
  Despite criticism of self-reported alcohol intake, it is a valuable tool to screen for alcohol abuse as a risk factor for cardiovascular disease. We aimed to compare various self-reported estimates of alcohol use with γ-glutamyltransferase (GGT) and percentage carbohydrate deficient transferrin (%CDT) considering their relationship with blood pressure changes (%BP) over a 5-year period in black South Africans.
  
  
  METHODS
  We recruited 1994 participants and collected 5-year followed up data (N = 1246). Participants completed questionnaires on alcohol intake indicating their former and current alcohol use ('yes' response and 'no' if alcohol was never used). We assessed alcohol intake (in g) using a quantified food frequency questionnaire. We collected blood samples and measured GGT and %CDT. Brachial BP (bBP) was measured at baseline and follow-up and central BP (cBP) at follow-up only.
  
  
  RESULTS
  Self-reported alcohol intake was significantly associated with the 5-year change in bBP before and after adjusting for confounders (%bSBP: R(2) = 0.263, β = 0.06, P = 0.023; %bDBP: R(2) = 0.326, β = 0.08 P = 0.005), as well as cSBP (R (2)= 0.286, β = 0.09, P = 0.010) and central pulse pressure (R(2) = 0.254, β = 0.06, P = 0.020). GGT and %CDT correlated well with self-reported alcohol intake (r = 0.44; P = 0.001; r = 0.34 P = 0.001), but did not associate significantly with %bBP or cBP at follow-up.
  
  
  CONCLUSIONS
  Self-reported alcohol use was strongly associated with a 5-year increase in BP in Africans with a low socio-economic status. This was not found for biochemical measures, GGT and %CDT. Self-reported alcohol intake could be an important measure to implement in primary healthcare settings in middle to low income countries, where honest reporting is expected.
authors.affiliation: aHypertension in Africa Research Team (HART) bCentre of Excellence for Nutrition cAfrica Unit for Transdisciplinary Health Research (AUTHeR), North-West University, Potchefstroom dDepartment of Physiology, University of Limpopo (Medunsa), Pretoria, South Africa.
authors.forename: Mandlenkosi C
authors.initials: MC
authors.lastname: Zatu
authors.forename: Johannes M
authors.initials: JM
authors.lastname: van Rooyen
authors.forename: Du Toit
authors.initials: du T
authors.lastname: Loots
authors.forename: Edelweiss
authors.initials: E
authors.lastname: Wentzel-Viljoen
authors.forename: Minrie
authors.initials: M
authors.lastname: Greeff
authors.forename: Aletta E
authors.initials: AE
authors.lastname: Schutte
mesh_terms: D000328:Adult; D000368:Aged; D000428:Alcohol Drinking; D000437:Alcoholism / Q000150:complications; D015415:Biomarkers / Q000097:blood*; D001794:Blood Pressure; D002241:Carbohydrates / Q000737:chemistry; D002318:Cardiovascular Diseases / Q000517:prevention & control; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000208:ethnology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D057566:Self Report; D013019:South Africa; D014168:Transferrin / Q000737:chemistry; D005723:gamma-Glutamyltransferase / Q000097:blood
chemical_list: D015415:Biomarkers; D002241:Carbohydrates; D014168:Transferrin; D005723:gamma-Glutamyltransferase