title: Lipid re-screening: what is the best measure and interval?
abstract: OBJECTIVE
  To estimate the long-term true change variation ('signal') and short-term within-person variation ('noise') of the different lipid measures and evaluate the best measure and the optimal interval for lipid re-screening.
  
  
  METHODS
  Retrospective cohort study from 2005 to 2008.
  
  
  METHODS
  A medical health check-up programme at a centre for preventive medicine in a teaching hospital in Tokyo, Japan.
  
  
  METHODS
  15 810 apparently healthy Japanese adults not taking cholesterol-lowering drugs at baseline, with a mean body mass index of 22.5 kg/m(2) (SD 3.2).
  
  
  METHODS
  Annual measurement of the serum total cholesterol (TC), low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and calculation of the ratio of TC/HDL and LDL/HDL. Measurement of the ratio of long-term true change variation ('signal') to the short-term within-person variation ('noise') for each measure.
  
  
  RESULTS
  At baseline, participants (53% male) with a mean age of 49 years (range 21-92) and a mean TC level of 5.3 mmol/l (SD 0.9 mmol/l) had annual check-ups over 4 years. Short-term within-person variations of TC, LDL, HDL, TC/HDL, and LDL/HDL were 0.12 (coefficient of variation (CV) 6.4%), 0.08 (CV 9.4%), 0.02 (CV 8.0%) mmol(2)/l(2), 0.08 (CV 7.9%) and 0.05 (CV 10.6%), respectively. The ratio of signal-to-noise at 3 years was largest for TC/HDL (1.6), followed by LDL/HDL (1.5), LDL (0.99), TC (0.8) and HDL (0.7), suggesting that cholesterol ratios are more sensitive re-screening measures.
  
  
  CONCLUSIONS
  The signal-to-noise ratios of standard single lipid measures (TC, LDL and HDL) are weak over 3 years and decisions based on these measures are potentially misleading. The ratios, TC/HDL and LDL/HDL, seem to be better measures for monitoring assessments. The lipid re-screening interval should be >3 years for those not taking cholesterol-lowering drugs.
authors.affiliation: Department of Primary Health Care, University of Oxford, Old Road Campus, Roosevelt Drive, Headington, Oxford, OX3 7LF, UK. otakahas@luke.or.jp
authors.forename: Osamu
authors.initials: O
authors.lastname: Takahashi
authors.forename: Paul P
authors.initials: PP
authors.lastname: Glasziou
authors.forename: Rafael
authors.initials: R
authors.lastname: Perera
authors.forename: Takuro
authors.initials: T
authors.lastname: Shimbo
authors.forename: Jiro
authors.initials: J
authors.lastname: Suwa
authors.forename: Sonoe
authors.initials: S
authors.lastname: Hiramatsu
authors.forename: Tsuguya
authors.initials: T
authors.lastname: Fukui
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D003327:Coronary Disease / Q000097:blood / Q000209:etiology; D005260:Female; D006801:Humans; D006949:Hyperlipidemias / Q000097:blood / Q000150:complications / Q000175:diagnosis*; D007564:Japan; D008055:Lipids / Q000097:blood*; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D015415:Biomarkers; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D008055:Lipids