title: Incidence of monoclonal gammopathy of undetermined significance and estimation of duration before first clinical recognition.
abstract: OBJECTIVE
  To determine the incidence of monoclonal gammopathy of undetermined significance (MGUS) in the general population and to estimate the duration of occult MGUS before first diagnosis.
  
  
  METHODS
  To estimate incidence we used innovative methods to exploit the Olmsted County, Minnesota, MGUS prevalence data, along with follow-up from a large cohort of patients with clinically detected MGUS. The prevalence cohort consisted of 21,463 persons systematically screened for the presence or absence of MGUS. The clinical cohort consisted of 7472 patients with MGUS diagnosed at Mayo Clinic from January 1, 1990, to May 13, 2010. The incidence of MGUS was estimated using the prevalence estimates, the rate of MGUS progression, and the death rates from MGUS using Markov chain methods.
  
  
  RESULTS
  We estimate that the annual incidence of MGUS in men is 120 per 100,000 population at the age of 50 years and increases to 530 per 100,000 population at the age of 90 years. The rates for women are 60 per 100,000 population at the age of 50 years and 370 per 100,000 population at the age of 90 years. We estimate that 56% of women 70 years of age diagnosed as having MGUS have had the condition for more than 10 years, including 28% for more than 20 years. Corresponding values for men are 55% and 31%, respectively. At 60 years of age, the proportion of prevalent cases that are clinically recognized is 13%. This rate increases to 33% at the age of 80 years.
  
  
  CONCLUSIONS
  In addition to an accumulation of cases, the age-related increase in prevalence of MGUS is related to a true increase in incidence with age. When first clinically recognized, MGUS has likely been present in an undetected state for a median duration of more than 10 years.
authors.affiliation: Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA.
authors.forename: Terry M
authors.initials: TM
authors.lastname: Therneau
authors.forename: Robert A
authors.initials: RA
authors.lastname: Kyle
authors.forename: L Joseph
authors.initials: LJ
authors.lastname: Melton
authors.forename: Dirk R
authors.initials: DR
authors.lastname: Larson
authors.forename: Joanne T
authors.initials: JT
authors.lastname: Benson
authors.forename: Colin L
authors.initials: CL
authors.lastname: Colby
authors.forename: Angela
authors.initials: A
authors.lastname: Dispenzieri
authors.forename: Shaji
authors.initials: S
authors.lastname: Kumar
authors.forename: Jerry A
authors.initials: JA
authors.lastname: Katzmann
authors.forename: James R
authors.initials: JR
authors.lastname: Cerhan
authors.forename: S Vincent
authors.initials: SV
authors.lastname: Rajkumar
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D015331:Cohort Studies; D005260:Female; D006304:Health Status; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D008998:Monoclonal Gammopathy of Undetermined Significance / Q000175:diagnosis* / Q000453:epidemiology*; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D017678:Sex Distribution; D055815:Young Adult