title: Thresholds for Serum 25(OH)D Concentrations With Respect to Different Outcomes.
abstract: BACKGROUND
  Vitamin D is essential for bone health. In addition, vitamin D has recently been proposed to play a role in the pathophysiology of many chronic diseases. Despite the large number of studies published on vitamin D, the threshold for a sufficient serum 25-hydroxyvitamin D [25(OH)D] concentration is still debated and may differ according to outcomes and subgroups.
  
  
  OBJECTIVE
  The objective of the study was to estimate the thresholds for serum 25(OH)D concentration with respect to the different outcomes and for different subgroups.
  
  
  METHODS
  Observational data from the Longitudinal Aging Study Amsterdam, an ongoing population-based Dutch cohort study [n = 1164, mean (SD) age 75.2 (6.5) y], were used.
  
  
  METHODS
  Falling, fractures, hypertension, cardiovascular disease, blood pressure, PTH, grip strength, physical performance, functional limitations, body mass index (BMI), and mortality were measured. To determine thresholds, spline curves were used. Visual inspection and the statistical best fit of the spline regression models were used together to estimate the best estimate of the thresholds.
  
  
  RESULTS
  Thresholds for serum 25(OH)D concentrations in the whole sample ranged from 46 nmol/L (PTH) to 68 nmol/L (hypertension). On average, women, the oldest old (≥ 75 y), and individuals with a high BMI (>25 kg/m(2)) had lower thresholds compared with men, the youngest old (65-75 y), and individuals with a low to normal BMI (<25 kg/m(2)).
  
  
  CONCLUSIONS
  The results indicate that thresholds for serum 25(OH)D may vary according to different outcomes and subgroups. This study does not support the high thresholds (>75 nmol/L) as advised by some experts, and the higher requirements in women, older persons, and those with high BMI.
authors: Department of Epidemiology and Biostatistics (E.S., M.W.H., N.M.S.), EMGO Institute for Health and Care Research, and Department of Internal Medicine (R.T.d.J., P.L.), Endocrine Section, VU University Medical Center, 1081 BT Amsterdam, The Netherlands.
authors: E
authors: E
authors: Sohl
authors: Department of Epidemiology and Biostatistics (E.S., M.W.H., N.M.S.), EMGO Institute for Health and Care Research, and Department of Internal Medicine (R.T.d.J., P.L.), Endocrine Section, VU University Medical Center, 1081 BT Amsterdam, The Netherlands.
authors: R T
authors: RT
authors: de Jongh
authors: Department of Epidemiology and Biostatistics (E.S., M.W.H., N.M.S.), EMGO Institute for Health and Care Research, and Department of Internal Medicine (R.T.d.J., P.L.), Endocrine Section, VU University Medical Center, 1081 BT Amsterdam, The Netherlands.
authors: M W
authors: MW
authors: Heymans
authors: Department of Epidemiology and Biostatistics (E.S., M.W.H., N.M.S.), EMGO Institute for Health and Care Research, and Department of Internal Medicine (R.T.d.J., P.L.), Endocrine Section, VU University Medical Center, 1081 BT Amsterdam, The Netherlands.
authors: N M
authors: NM
authors: van Schoor
authors: Department of Epidemiology and Biostatistics (E.S., M.W.H., N.M.S.), EMGO Institute for Health and Care Research, and Department of Internal Medicine (R.T.d.J., P.L.), Endocrine Section, VU University Medical Center, 1081 BT Amsterdam, The Netherlands.
authors: P
authors: P
authors: Lips
mesh_terms: D000058:Accidental Falls / Q000706:statistics & numerical data; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood; D001794:Blood Pressure; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000097:blood / Q000453:epidemiology; D002908:Chronic Disease / Q000453:epidemiology*; D005260:Female; D050723:Fractures, Bone / Q000097:blood / Q000453:epidemiology; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000453:epidemiology; D008137:Longitudinal Studies; D008297:Male; D051346:Mobility Limitation; D009426:Netherlands / Q000453:epidemiology; D010281:Parathyroid Hormone / Q000097:blood; D011379:Prognosis; D012016:Reference Values; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000150:complications* / Q000175:diagnosis* / Q000453:epidemiology* / Q000503:physiopathology
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D