measurement for men. For women: r=0.36. Nutrition survey of elderly in UK (Margetts, p 211) Vitamin B6 Plasma Validity 0.37 Correlation between B6 and plasma Urinary Validity - pyridoxal phosphate levels in 280 healthy men =0.37 (Willett p203) Folacin Validity 0.56 Correlation of 0.56 in Framington Heart Erythrocyte 0.51 study 385 subjects (serum) Correlation in 19 elderly subjects (erythrocyte) (Willet p204) Magnesium Serum Validity 0.27 Correlation between intake with supplements 0.27 in 139 men and 0.15 without supplements (Willett p211) Iron (ferritin) Serum Validity 0.16 Borderline 0.16 correlation with heme intake but only r-0.15 with total intake (Willett p 208). Included as marker of iron storage Copper Erythrocyte - - S.O.D levels reflect both depletion and (Superoxide repletion of Cu (Willett p 212) dismutase) Selenium Validity 0.63 Correlation between selenium intake and serum selenium in South Dakotans (n=44)(Willett, p 186) Reproducibility 0.76 Average correlation between repeated measurements at four 3-month intervals in 78 adults (Willett, p 188) Toenails Validity 0.59 Correlation between selenium intake and toenail selenium level in South Dakotans (n=44) (Willett, p 186)` Reproducibility 0.48 Correlation for selenium levels in toenails collected 6 apart from 127 US women (Willett, p 206) Whole Validity 0.62 Correlation between selenium intake blood and blood selenium in South Dakotans (n=44) (Willett, p 186) Reproducibility 0.95 Average correlation between repeated measurements at four 3-month intervals in 78 adults (Willett, p 188) Linoleic acid Adipose Validity 0.57 Correlation between dietary linoleic tissue acid intakes determined from 7-day weighted diet records and the relative proportion of linoleic acid in adipose tissue in Scottish men (n=164). Also correlation between linoleic acid measured in adipose tissue and calculated from FFQ in 118 Boston-area men (Willett, p 220)
measurement for men. For women: r=0.36. Nutrition survey of elderly in UK (Margetts, p 211) Vitamin B6 Plasma Urinary Validity Validity 0.37 - Correlation between B6 and plasma pyridoxal phosphate levels in 280 healthy men =0.37 (Willett p203) Folacin Erythrocyte Validity 0.56 0.51 Correlation of 0.56 in Framington Heart study 385 subjects (serum) Correlation in 19 elderly subjects (erythrocyte) (Willet p204) Magnesium Serum Validity 0.27 Correlation between intake with supplements 0.27 in 139 men and 0.15 without supplements (Willett p211) Iron (ferritin) Serum Validity 0.16 Borderline 0.16 correlation with heme intake but only r-0.15 with total intake (Willett p 208). Included as marker of iron storage Copper (Superoxide dismutase) Erythrocyte - - S.O.D levels reflect both depletion and repletion of Cu (Willett p 212) Selenium Validity 0.63 Correlation between selenium intake and serum selenium in South Dakotans (n=44)(Willett, p 186) Reproducibility 0.76 Average correlation between repeated measurements at four 3-month intervals in 78 adults (Willett, p 188) Toenails Validity 0.59 Correlation between selenium intake and toenail selenium level in South Dakotans (n=44) (Willett, p 186)` Reproducibility 0.48 Correlation for selenium levels in toenails collected 6 apart from 127 US women (Willett, p 206) Whole blood Validity 0.62 Correlation between selenium intake and blood selenium in South Dakotans (n=44) (Willett, p 186) Reproducibility 0.95 Average correlation between repeated measurements at four 3-month intervals in 78 adults (Willett, p 188) Linoleic acid Adipose tissue Validity 0.57 Correlation between dietary linoleic acid intakes determined from 7-day weighted diet records and the relative proportion of linoleic acid in adipose tissue in Scottish men (n=164). Also correlation between linoleic acid measured in adipose tissue and calculated from FFQ in 118 Boston-area men (Willett, p 220)