Quality Assessment of 25(OH)D, Insulin, Total Cholesterol, Triglycerides, and Potassium in 40-Year-Old Frozen Serum

• Background: Many longitudinal epidemiological studies collect specimens into biobanks to investigate how biomarkers predict future disease. In 1968-1969, the Population Study of Women in Gothenburg (PSWG) established a biobank. Objective: To examine the validity of 25-hydroxyvitamin D (25(OH)D), total cholesterol, triglycerides, insulin and potassium after 40 years of storage at -20⁰C in terms of relative and absolute agreement. The quality of these markers under such condition has not been previously investigated. Methods: Baseline- and re-measured levels were compared in selected samples through percentage change, correlation and regression. 25(OH)D levels, not assessed at baseline, were compared by season, by BMI and longitudinally over six years. Results: Despite some lack of absolute agreement, Spearman correlations were >0.7 and statistically significant for all biomarkers. The 1968-1969 25(OH)D correlated with BMI (r=-0.45, p=0.05) and with levels six years later (r=0.85, p<0.001). Summer 25(OH)D was higher than winter 25(OH)D (p=0.02). Conclusion: For all markers, baseline- and re-measured levels exhibited high relative agreement. 25(OH)D was comparable with expected levels on fresh blood and varied with season. In future studies, PSWG individuals will be ranked according to these markers in order to follow incidence of disease.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Hälsovetenskap -- Folkhälsovetenskap, global hälsa, socialmedicin och epidemiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Health Sciences -- Public Health, Global Health, Social Medicine and Epidemiology (hsv//eng)

Nyckelord

vitamin D

25(OH)D

long-term stored serum

biobank

triglycerides

insulin

total cholesterol

potassium

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)