The relation between nutritional factors and insulin-like growth factor-I in premenopausal women of different ethnicity.
BACKGROUND
Alterations in the insulin-like growth factor-I (IGF-I) system have been proposed as a metabolic link between nutritional factors and cancer risk.


OBJECTIVE
This study explored dietary determinants of circulating IGF-I and IGF binding protein-3 (IGFBP-3) levels among premenopausal women from different ethnic groups.


METHODS
In a cross-sectional design, 258 women with a mean age of 43 +/- 2.7 years donated blood approximately 5 days after ovulation and completed a validated Food Frequency Questionnaire. The majority of the 97 Caucasian, 96 Asian, and 65 Mixed/Other subjects were born in the US. Serum concentrations of IGF-I and IGFBP-3 were measured by double-antibody ELISA. After creating quartiles for 13 food and 13 nutrient density variables, least-square means of IGF-I, IGFBP-3, and the IGF-I/IGFBP-3 ratio were calculated by quartile, while adjusting for age, ethnicity, body mass index, and year of laboratory analysis.


RESULTS
Whereas body mass index and dietary intakes varied significantly by ethnicity, IGF-I, IGFBP-3, and their ratio were similar by group. As the only food, fish showed a suggestive inverse association with IGF-I and the IGF-I/ IGFBP-3 ratio. Dietary fiber and vitamin A were positively related to IGF-I (p = 0.004 and 0.03), zinc with IGFB-3 (p = 0.0008), and iron with the IGF-I/IGFBP-3 ratio (p = 0.048), but the differences between the bottom and top quartile were less than 10%. Total energy, protein, carbohydrates, and total fat intake were not related to any serum measurements.


CONCLUSIONS
This study detected no ethnic differences in serum IGF-I, but it showed weak associations with dietary variables that require further investigation.
Cancer Research Center of Hawaii, 1236 Lauhala Street, Honolulu, HI 96813, USA. gertraud@crch.hawaii.edu
Gertraud
G
Maskarinec
Yumie
Y
Takata
Rudolph
R
Kaaks
D000328:Adult; D001208:Asia / Q000208:ethnology; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005006:Ethnicity / Q000706:statistics & numerical data*; D005247:Feeding Behavior / Q000208:ethnology; D005260:Female; D006254:Hawaii; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008875:Middle Aged; D009369:Neoplasms / Q000097:blood / Q000453:epidemiology / Q000517:prevention & control; D017697:Premenopause / Q000097:blood* / Q000208:ethnology; D012307:Risk Factors; D011795:Surveys and Questionnaires; D044465:White People / Q000706:statistics & numerical data
D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I