Insulin-like growth factor-I, soy protein intake, and breast cancer risk

Previous studies have found that estrogen enhances the effect of insulin-like growth factor-I (IGF-I) levels on breast cancer cell growth. Participants in the Shanghai Breast Cancer Study (SBCS) consumed large amounts of soy that was high in isoflavones, which act as weak estrogens and as anti-estrogens. We assessed whether soy protein intake modified the effect of IGF-I levels on breast cancer risk. The SBCS is a population-based case-control study of breast cancer among women aged 25-64 conducted between 1996 and 1998 in urban Shanghai. In-person interviews were completed with 1,459 incident breast cancer cases ascertained through a population-based cancer registry and 1,556 controls randomly selected from the general population (with respective response rates of 91% and 90%). This analysis is restricted to the 397 cases and 397 matched controls for whom information on IGF-I levels was available. For premenopausal breast cancer, we found nearly significant interactions between soy protein intake and IGF-I levels (P = 0.080) and insulin-like growth factor-binding protein-3 (IGFBP-3) levels (P = 0.057). The direction of the interaction appeared to be negative for IGF-I levels but was positive for IGFBP-3 levels. No interaction was evident between soy protein intake and IGF-I or IGFBP-3 levels among postmenopausal women. Our results suggest that soy protein intake may negatively modulate the effect of IGF-I and may positively modulate the effect of IGFBP-3 levels on premenopausal breast cancer risk. Further studies are needed to confirm our finding and to understand the biological mechanisms of these potential interactions.     

Insulin-like growth factor-1 and binding protein-3 in a 2-year soya intervention among premenopausal women

Soya foods may protect against the development of breast cancer. Insulin-like growth factor (IGF)-1 is under investigation as a possible link between nutrition and cancer. We examined the effect of soya foods on circulating IGF-1 and IGF binding protein (BP)-3 levels among 196 healthy premenopausal women in a 2-year randomised nutritional trial. The intervention group consumed two daily servings of soya foods including tofu, soya milk, soya nuts and soya protein powder (equivalent to 50 mg isoflavones and 5-22 g soya protein per serving); the controls maintained their regular diet. Five serum samples at baseline, 3, 6, 12, and 24 months were collected in the morning during the luteal phase and analysed for IGF-1 and IGFBP-3 by double-antibody ELISA. We applied mixed models to investigate the intervention effect and predictors of serum levels while considering the repeated measurement design. Adherence with the study regimen was high and dropout rates were acceptable. Randomisation resulted in similar mean IGF-1 and IGFBP-3 levels by group. We did not observe a significant intervention effect on IGF-1, IGFBP-3, and their molar ratio during the entire study period. However, urinary isoflavone excretion during the study period was positively associated with IGF-1 (P=0.04) and the IGF-1:IGFBP-3 ratio (P=0.06). The effect was consistent over time. Adding soya foods to the diet of premenopausal women does not appear to lower serum levels of IGF-1 and IGFBP-3; if anything, the greater protein intake from soya may lead to a small increase in IGF-1 serum levels.     

胰岛素样生长因子及其结合蛋白与妊娠期高血压疾病的相关性研究

目的:研究妊娠期高血压疾病患者血清胰岛素样生长因子-1(IGF-1)、胰岛素样生长因子结合蛋白-1(IGFBP-1)的水平与病情程度及新生儿出生体重之间的关系。方法:采用放射免疫方法测定并比较38例妊娠期高血压疾病患者与38例正常血压妊娠妇女的血清IGF-1、IGFBP-1的水平。结果:子痫前期组IGF-1显著低于妊娠期高血压组和正常组,而IGFBP-1水平显著高于妊娠期高血压组和正常组;妊娠期高血压组与正常组间IGF-1、IGFBP-1的水平比较,差异均无统计学意义。IGF-1水平与收缩压、舒张压及平均动脉压呈显著负相关,与新生儿出生体重呈显著正相关,而IGFBP-1与收缩压、舒张压及平均动脉压呈显著正相关,与新生儿出生体重呈显著负相关。结论:妊娠期高血压疾病患者的发病及严重程度与IGF-1、IGFBP-1有明显的关系,IGF-1、IGFBP-1与胎儿的发育及新生儿出生体重有明显的相关性。     

血清IGF-1、IGFBP-3水平和大肠癌关系的Meta分析

目的综合评价血清胰岛素样生长因子-1(IGF-1)、胰岛素样生长因子结合蛋白-3(IGFBP-3)水平和大肠癌的关系。方法利用Meta分析法对6篇关于血清IGF-1、IGFBP-3水平与大肠癌关系的研究文献进行定量综合分析。结果对于IGF-1，合并OR=1．56(95％CI：1．14～2．13)；按实验方法不同分层，间接酶联免疫吸附试验(ELISA)合并OR=1．92(95％CI：1．26～2．93)，IRMA法合并OR=1．23(95％CI：0．78～1．94)；对于IGFBP-3，合并OR=0．78(95％CJ：0．43～1．44)；按实验方法不同分层，ELISA法合并OR=0．46(95％CI：0．29～0．74)，免疫放射测定法(IRMA)合并OR=1．44(95％CI：0．93～2．23)。结论血清IGF-1高水平为大肠癌的独立危险因子，IGFBP-3与大肠癌的关联不具有统计学意义；IGFBP-3与大肠癌关系的各研究之间异质性是由实验方法不同而引起，但该结论尚需大样本并同时进行两种方法的测量证实。     

非营养性吸吮对早产儿血清IGF-1、IGFBP-3及生长发育的影响

目的:探讨非营养性吸吮对早产儿血清IGF-1、IGFBP-3及生长发育的影响。方法:以2008年9月～2009年8月收治的早产儿60例为研究对象,随机分为非营养性吸吮(NNS)组和对照组,采用ELISA法测定生后第1天开奶前及生后第3天、第7天、第14天血清IGF-1、IGFBP-3水平,同时记录生长发育指标(头围、身长)。结果:①NNS组血清IGF-1、IGFBP-3水平在生后第7、14天高于对照组(P<0.05)。②与对照组相比,NNS组第14天头围、体重增长差异有统计学意义(P<0.01)。③血清IGF-1与头围、体重增长呈正相关(r=0.684,P<0.01;r=0.656,P<0.01),与血清IGFBP-3水平呈正相关(r=0.659,P<0.01)。结论:NNS能提高血清IGF-1、IGFBP-3水平,加快早产儿的生长发育。     

Effect of lycopene supplementation on insulin-like growth factor-1 and insulin-like growth factor binding protein-3: a double-blind, placebo-controlled trial

OBJECTIVE: Studies have suggested a link between lycopene and insulin-like growth factor-1 (IGF-1). The aim of this study was to test the effect of lycopene supplementation on IGF-1 and binding protein-3 (IGFBP-3) status in healthy male volunteers. DESIGN, SETTING, SUBJECTS AND INTERVENTION: This was a 4 week randomized, double-blind, placebo-controlled study of lycopene supplementation (15 mg/day) in healthy male volunteers (n=20). Fasting blood samples were collected at baseline and after 4 weeks. Samples were analysed for lycopene by high-performance liquid chromatography (HPLC) and IGF-1 and IGFBP-3 by enzyme-linked immunosorbent assay (ELISA). Changes in end points from baseline were compared in those who received placebo versus those who received the lycopene supplement. RESULTS: Median change in lycopene from baseline (post-supplement - baseline) was higher in subjects in the intervention than those on placebo (lycopene group 0.29 (0.09, 0.46); placebo group 0.03 (-0.11, 0.08) micromol/l; median (25th, 75th percentiles), P<0.01). There was no difference in median change in IGF-1 concentrations (lycopene group -0.6 (-2.6, 1.9); placebo group -1.15 (-2.88, 0.95) nmol/l, P=0.52), or median change in IGFBP-3 concentrations (lycopene group 245 (-109, 484); placebo group 101 (-34, 234) nmol/l, P=0.55) between intervention and control groups. Change in lycopene concentration was associated with the change in IGFBP-3 in the intervention group (r=0.78; P=0.008; n=10). CONCLUSIONS: Lycopene supplementation in healthy male subjects has no effect on IGF-1 or IGFBP-3 concentrations in a healthy male population. However, the association between change in lycopene concentration and change in IGFBP-3 in the intervention group suggests a potential effect of lycopene supplementation on IGFBP-3.     

Effect of a tomato drink intervention on insulin-like growth factor (IGF)-1 serum levels in healthy subjects

There is concern that dietary factors can modulate the insulin-like growth factor (IGF) system. The aim of this work was to evaluate the effect of a tomato drink intervention providing small amounts of lycopene and other carotenoids on serum levels of IGF-1. Twenty healthy young subjects participated in a repeated measure double-blind, cross-over design. Subjects consumed 250 ml of a tomato drink or a placebo drink for 26 days separated by 26 days wash-out. The tomato drink intake increased plasma lycopene, phytoene, phytofluene, and beta-carotene concentrations by 0.22, 0.12, 0.13, and 0.18 micromol/L, respectively (P < 0.05). No significant effect of the tomato drink intake on IGF-1 levels was observed. However, changes in lycopene before and after each experimental period were inversely and significantly correlated with those of IGF-1 (r = -0.33, P < 0.05, N = 20). No correlation was found with the other carotenoids. A significant reduction of IGF-1 serum level (-5.7%) was observed in subjects (n = 11) with the highest plasma lycopene response but also IGF-1 levels following the tomato drink intake (P < 0.05). No effect was evident after the placebo treatment. The results suggest that further exploration of the role of tomato lycopene on IGF-1 modulation both on healthy and on subjects at risk is necessary.     

IGF-1, IGFBP-3, and nutritional factors in young black and white men: the CARDIA Male Hormone Study

Nutritional factors might play a role in regulating serum levels of insulin-like growth factors (IGFs), which are associated with some cancers. We examined the associations of nutritional factors with IGF-1 and IGF binding protein-3 (IGFBP-3). Serum IGF-1 and IGFBP-3 levels and dietary intake were measured in 459 black and 682 white male subjects of the Coronary Artery Risk Development in Young Adults study at the Year 7 (1992-1993) exam. Analysis of covariance and multivariable linear regression were used to assess associations of IGFs with dietary factors by race. IGF-1 was positively associated with magnesium in both black and white men (P = 0.008 and 0.05, respectively). Calcium was positively significantly related to IGF-1 in black men (P = 0.04) and marginally so in white men (P = 0.09). In black men, IGFBP-3 was positively associated with magnesium (P = 0.02), and one serving of milk per day was associated with an 8.23-ng/ml higher IGF-1 concentration (P = 0.05). Tests for interaction, however, revealed no differences between blacks and whites in the associations of nutrients with IGF-1 or IGFBP-3. In conclusion, the associations of dietary factors with serum IGF-1 and IGFBP-3 observed in our study corroborate those from other studies and generally do not differ between black and white men.     

不同出生胎龄的2～7岁小于胎龄儿生长激素释放多肽、胰岛素样生长因子-1、胰岛素水平及其与生长发育的关系

目的探讨生长激素释放多肽(Ghrelin)、胰岛素样生长因子-1(IGF-1)、胰岛素样生长因子结合蛋白-3(IGFBP-3)、胰岛素在小于胎龄儿(SGA)生长发育中的作用。方法分别检测2～7岁早产SGA、足月SGA血Ghrelin、IGF-1、IGFBP-3、胰岛素、血糖的水平,并与相应的早产AGA、足月AGA进行比较,并做相关性分析。结果 Ghrelin在早产SGA组高于足月SGA(P<0.05),与早产AGA无明显差异,早产AGA高于足月AGA(P<0.05),足月SGA高于足月AGA(P<0.01)。IGF-1和IGFBP-3水平在早产SGA组低于足月SGA(P<0.05),早产AGA组明显低于足月AGA组(P<0.0001)。胰岛素水平在足月SGA组最高。胰岛素抵抗指数(IRI)在各组间比较与胰岛素结果一致。早产SGA组与足月SGA组中Ghrelin与各项指标的相关分析显示:Ghrelin与体重标准差计分(SDS)、IGF-1、IGFBP-3、胰岛素及IRI呈负相关,早产SGA组分别为(r=-0.683,P<0.002;r=-0.749,P<0.001;r=-0.828,P<0.001;r=-0.694,P<0.005;r=-0.822,P<0.001),足月SGA组分别为(r=-0.792,P<0.001;r=-0.707,P<0.002;r=-0.615,P<0.01;r=-0.648,P<0.005;r=-0.679,P<0.005)。结论 Ghrelin参与了早产儿和SGA儿生后的生长发育过程,但与追赶生长程度的关系不大。Ghrelin作为胰岛素的反调节因子,以负反馈的形式调节能量代谢。     

Insulin-like growth factor-1, insulin-like growth factor binding protein-3, and cardiovascular disease risk factors in young black men and white men: the CARDIA Male Hormone Study

Cross-sectional studies have found associations between components of the insulin-like growth factor (IGF) system and hypertension, total cholesterol, and low density lipoprotein cholesterol. Using partial correlation analysis and longitudinal analysis of data collected at the year 2, year 7, and year 10 examinations, the authors assessed the associations of IGF-1 and IGF binding protein-3 (IGFBP-3) with cardiovascular disease risk factors in 544 Black and 747 White male participants in the Coronary Artery Risk Development in Young Adults (CARDIA) Male Hormone Study who were aged 20-34 years at year 2 (1987-1988). There were no consistent independent associations with blood pressure. Cross-sectionally, there were some inverse associations between IGF-1 and lipid levels in White men (strongest r = -0.095 (p = 0.02) for total cholesterol at year 7) and positive associations between IGFBP-3 and lipid levels in Black and White men (for log(triglycerides), r = 0.072-0.136). Longitudinally, a 1,000-ng/ml increase in IGFBP-3 was associated with 3.7-mg/dl and 2.6-mg/dl higher total cholesterol levels and 2.6-mg/dl and 1.7-mg/dl higher low density lipoprotein cholesterol levels in Black men and White men (p < 0.05), respectively. These findings do not support a strong link between IGF-1 and IGFBP-3 and blood pressure, but they do support the possibility of important relations between IGFBP-3 and lipid levels in young adult men.     

Soy isoflavones do not modulate circulating insulin-like growth factor concentrations in an older population in an intervention trial

Insulin-like growth factors (IGF) are essential for normal growth and maintenance of lean muscle mass; however, high insulin-like growth factor-I (IGF-I) and low IGF binding protein-3 (IGFBP-3) levels are also associated with several cancers. To test the hypothesis that long-term soy isoflavone supplementation decreases circulating IGF-I concentrations, we conducted a controlled, parallel-arm, double-blind intervention study with 150 participants (85% men), 50-80 y old. Participants were randomly assigned to consume a soy beverage powder daily for 12 mo. The active treatment group (+ISO) received soy protein containing 83 mg isoflavones, whereas the comparison group (-ISO) received soy protein containing 3 mg isoflavones. Serum IGF-I and IGFBP-3 were measured by ELISA. Mean change in serum IGF-I concentrations was similar in the two groups (+1.4 nmol/L in +ISO, +1.2 nmol/L in -ISO; P = 0.74, 95% confidence interval -1.1, +1.5 nmol/L for the 0.21 nmol/L difference between groups), indicating no effect of the isoflavone intervention. Similarly, the changes in IGFBP-3 and the IGF-I/IGFBP-3 ratio were similar in both groups, again showing no effect of +ISO treatment. A 12 mo, 83 mg/d soy isoflavone intervention did not modulate serum IGF in an older, mostly male population.     

Relationship of dietary protein and soy isoflavones to serum IGF-1 and IGF binding proteins in the Prostate Cancer Lifestyle Trial

High levels of insulin-like growth factor 1 (IGF-1) are associated with increased risk of prostate cancer, whereas increased levels of some of its binding proteins (IGFBPs) seem to be protective. High intakes of dietary protein, especially animal and soy protein, appear to increase IGF-1. However, soy isoflavones have demonstrated anti-proliferative and apoptotic effects both in vitro and in vivo. We evaluated dietary intakes of total protein and soy isoflavones in relation to the IGF axis in prostate cancer patients making comprehensive lifestyle changes including a very low-fat vegan diet supplemented with soy protein (58 g/day). After one year, intervention group patients reported significantly higher intakes of dietary protein and soy isoflavones compared to usual-care controls (P < 0.001). IGF-1 increased significantly in both groups, whereas IGFBP-1 rose in the experimental group only (P < 0.01). Increases in vegetable protein over one year were associated with increases in IGFBP-1 among intervention group patients (P < 0.05). These results suggest that dietary protein and soy isoflavones, in the context of comprehensive lifestyle changes, may not significantly alter IGF-1. However, given the recent literature indicating that high intake of protein rich in essential amino acids (animal or soy protein) may increase IGF-1, it may be prudent for men with early stage prostate cancer not to exceed dietary protein recommendations.     

胰岛素样生长因子在诊断儿童生长激素缺乏症中的临床价值

目的 探讨胰岛素样生长因子-1(IGF-1)、胰岛素样生长因子结合蛋白-3(IGFBP-3)检测在诊断矮小儿童生长激素缺乏症的临床价值。方法 收集65例临床诊断为矮小儿童血清标本,其中生长激素缺乏(GHD)组52例,特发性矮小症(ISS)组13例。收集46名健康儿童血清标本作为对照组。用化学发光法分别检测血清IGF-1和IGFBP-3浓度。结果 与对照组比较,GHD组和ISS组患儿血清IGF-1和IGFBP-3浓度均显著降低,差异均有统计学意义(P<0.05);GHD组血清IGF-1、IGFBP-3浓度分别为(105.53±75.22)ng/mL、(2.52±1.06)μg/mL,ISS组分别为(197.41±87.43)ng/mL、(3.61±1.50)μg/mL,差异有统计学意义(P<0.05)。结论 IGF-1、IGFBP-3可以为临床诊断矮小儿童生长激素缺乏症提供重要参考价值。     

Relationship of Dietary Protein and Soy Isoflavones to Serum IGF-1 and IGF Binding Proteins in the Prostate Cancer Lifestyle Trial

High levels of insulin-like growth factor 1 (IGF-1) are associated with increased risk of prostate cancer, whereas increased levels of some of its binding proteins (IGFBPs) seem to be protective. High intakes of dietary protein, especially animal and soy protein, appear to increase IGF-1. However, soy isoflavones have demonstrated anti-proliferative and apoptotic effects both in vitro and in vivo. We evaluated dietary intakes of total protein and soy isoflavones in relation to the IGF axis in prostate cancer patients making comprehensive lifestyle changes including a very low-fat vegan diet supplemented with soy protein (58 g/day). After one year, intervention group patients reported significantly higher intakes of dietary protein and soy isoflavones compared to usual-care controls (P < 0.001). IGF-1 increased significantly in both groups, whereas IGFBP-1 rose in the experimental group only (P < 0.01). Increases in vegetable protein over one year were associated with increases in IGFBP-1 among intervention group patients (P < 0.05). These results suggest that dietary protein and soy isoflavones, in the context of comprehensive lifestyle changes, may not significantly alter IGF-1. However, given the recent literature indicating that high intake of protein rich in essential amino acids (animal or soy protein) may increase IGF-1, it may be prudent for men with early stage prostate cancer not to exceed dietary protein recommendations.     

结节性甲状腺肿血清胰岛素样生长因子-1水平与摄131Ⅰ率相关性研究

目的 研究结节性甲状腺肿患者血清胰岛素样生长因子-1(IGF-1)水平与甲状腺摄131 Ⅰ率的相关性,为临床鉴别甲状腺结节的性质寻找更简捷、安全的方法.方法 60例甲状腺结节患者分为热结节组(30例)和冷结节组(30例),以常规体检的健康人员30例作为对照组.采用放射免疫分析法检测血清IGF-1、游离三碘甲状腺原氨酸(FT3)、游离甲状腺素(FT4)、TSH的含量,常规放射性核素扫描技术检测甲状腺摄131 Ⅰ率.结果 与对照组比较,热结节组患者血清IGF-1 [(315.86±22.74)μg/L]、FT3[(15.32±8.65)pmol/L]、FT4[(86.82±35.22)pmol/L]水平明显增高,摄131 Ⅰ率(0.64±0.17)明显增高,血清TSH[(0.28±0.31)mU/L]水平明显降低,P<0.01.热结节组IGF-1水平与摄131 Ⅰ率呈正相关(r=0.835),与TSH水平呈轻度负相关(r=-0.326).而冷结节组患者血清IGF-1、FT3、FT4、TSH水平与对照组比较差异无统计学意义(P>0.05).结论 血清IGF-1水平与甲状腺摄131 Ⅰ率有一定的相关性.     

阻塞性睡眠呼吸暂停低通气综合征儿童血清生长因子表达的影响因素分析

目的 分析阻塞性睡眠呼吸暂停低通气综合征(OSAHS)患儿血清胰岛素样生长因子-1(IGF-1)、胰岛素样生长因子结合蛋白-3(IGFBP-3)水平的变化及其影响因素。方法 纳入2012年7月-2015年7月在昆明市儿童医院住院的3~6岁220例OSAHS患儿和40例非睡眠呼吸障碍患儿。按呼吸暂停低通气指数(AHI)将OSAHS患儿分为轻度、中度、重度OSAHS组。检测所有儿童血清IGF-1、IGFBP-3水平,体重指数(BMI)、身高及体重,比较各组间的差异,并采用多元逐步回归分析探讨影响患儿血清IGF-1、IGFBP-3水平的因素。结果 重度OSAHS组血清IGF-1水平[(121.86±36.47)μg/L]显著低于对照组[(149.44±31.44)μg/L]、轻度OSAHS组[(147.63±26.83)μg/L]和中度OSAHS组[(142.11±34.50)μg/L](P均＜0.05),重度OSAHS组身高显著低于对照组(102.64±5.95)cm vs(105.22±6.03) cm,P＜0.05)。血清IGFBP-3水平、BMI和体重在各组间差异无统计学意义(P均＞0.05)。经多元逐步回归分析结果显示OSAHS组的血清IGF-1、IGFBP-3水平受年龄、平均最低血氧饱和度(LSaO₂)的影响。结论 OSAHS患儿生长发育迟缓可能与血清IGF-1水平降低有关,缺氧是影响OSAHS患儿血清IGF-1水平变化的因素。     

Low-fat diet with omega-3 fatty acids increases plasma insulin-like growth factor concentration in healthy postmenopausal women

The insulin-like growth factor pathway plays a central role in the normal and abnormal growth of tissues; however, nutritional determinants of insulin-like growth factor I (IGF-I) and its binding proteins in healthy individuals are not well defined. Three test diets—high-fat diet (40% energy as fat), low-fat diet (LF; 20% energy as fat), and a diet with low fat and high omega-3 fatty acid (LFn3; 23% energy as fat)—were tested in a randomized crossover designed controlled feeding trial in healthy postmenopausal women. Plasma IGF-I, IGF binding protein-3 (IGFBP-3), insulin, glucose, and ratio of IGF-I/IGFBP-3 concentrations were measured in response to diets. Insulin sensitivity was calculated using the homeostatic model assessment of insulin resistance We hypothesized that IGF-I, insulin, and glucose concentrations would decrease and IGFBP-3 concentration would increase in response to the low-fat diets. Eight weeks of the LFn3 diet increased circulating IGF-I (P < .001) and IGFBP-3 (P = .01) and the LF diet increased IGFBP-3 (P = .04), resulting in trends toward an increased IGF-I/IGFBP-3 ratio with the LFn3 diet and a decreased IGF-I/IGFBP-3 ratio with the LF diet (P = .13 for both comparisons). No statistically significant differences were detected between treatments at baseline or 8 weeks for IGF-1, IGFBP-3, or the ratio of IGF-1/IGFBP-3. Insulin, glucose, and the homeostatic model assessment of insulin resistance were not altered by the interventions. Low-fat diet with high n-3 fatty acids may increase circulating IGF-I concentrations without adversely affecting insulin sensitivity in healthy individuals.     

Epidemiology of the insulin-like growth factor system in three ethnic groups.

The insulin-like growth factor (IGF) system, comprising insulin-like growth factor I (IGF-I), insulin-like growth factor II (IGF-II), and their binding proteins (IGFBPs), is linked to cell growth, the development of cardiovascular disease, and several cancers. Little is known about its epidemiology. The authors studied relations of the IGF system to anthropometric and metabolic variables in three population-based ethnic groups in Manchester, England, in 1994-1998 with differing disease risks: African Caribbean (n = 193), Pakistani (n = 130), and local Europeans(n = 142). Standardized anthropometry, glucose tolerance tests, and serum assays were performed. Body mass indices (BMIs) were high in all groups. IGF-I levels were highest in normoglycemic African Caribbeans and declined with age (r = -0.28). IGF-II levels were greatest in Europeans. IGFBP-1 concentrations increased with age in Pakistanis (r = 0.20) and Europeans (r = 0.29), but not in African Caribbeans (r = 0.06), and were inversely related to BMI (r = -0.37). Age- and sex-adjusted IGFBP-1 was inversely related to fasting insulin and proinsulin in all groups; participants with newly detected diabetes were relatively insulinopenic but had higher IGFBP-1 concentrations. Nonesterified (free) fatty acid (NEFA) concentrations increased with declining glucose tolerance. In multiple regression analysis, IGFBP-1 was independently and negatively related to fasting insulin, BMI, and African-Caribbean compared with European ethnicity but positively related to age, fasting glucose, and NEFA. IGF-I was inversely related only to age, NEFA, and Pakistani ethnicity. IGF-II showed a strong ethnic difference but was unrelated to other variables. These data indicate considerable potential for exploring disease-IGF system relations in population samples.     

Associations of Current,Childhood, and Adolescent Milk Intake with Serum Insulin-like Growth Factor (IGF)-1 and IGF Binding Protein 3 Concentrations in Adulthood

Previous studies have shown that insulin-like growth factor (IGF)-1 levels are positively and IGF binding protein (IGFBP)-3 levels negatively associated with risk of certain cancers. Also, dietary factors may influence the IGF system. We aimed to analyze the associations of current, childhood and adolescent milk intake with IGF-1 levels, IGFBP-3 levels and IGF-1:IGFBP-3 molar ratio in adulthood. Multivariable linear regression analyses by sex and race/ethnicity were performed using cross-sectional data from the Third National Health and Nutrition Examination Survey. A total of 5,805 participants were included in the analyses. Adult IGF-1 levels and IGF-1:IGFBP-3 molar ratio had significant inverse associations (P-trend = 0.02) with adolescent milk intake in non-Hispanic white men, but not in men of other race/ethnicities or in women. There were no associations between current or childhood milk intake and IGF-1 levels or IGF-1:IGFBP-3 molar ratio in adulthood. Current milk intake and childhood milk intake had significant positive associations (P-trend = 0.02) with adult IGFBP-3 levels in non-Hispanic white and non-Hispanic black women, respectively, but no associations were observed in Mexican American women or in men. Overall, there were long-term and short-term associations between milk intake and IGF-1 and IGFBP-3 levels, but the associations varied by race/ethnicity and sex.