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。     

Interactions between genome-wide significant genetic variants and circulating concentrations of insulin-like growth factor 1, sex hormones, and binding proteins in relation to prostate cancer risk in the National Cancer Institute Breast and Prostate Cancer Cohort Consortium

Genome-wide association studies (GWAS) have identified many single nucleotide polymorphisms (SNPs) associated with prostate cancer risk. There is limited information on the mechanistic basis of these associations, particularly about whether they interact with circulating concentrations of growth factors and sex hormones, which may be important in prostate cancer etiology. Using conditional logistic regression, the authors compared per-allele odds ratios for prostate cancer for 39 GWAS-identified SNPs across thirds (tertile groups) of circulating concentrations of insulin-like growth factor 1 (IGF-1), insulin-like growth factor binding protein 3 (IGFBP-3), testosterone, androstenedione, androstanediol glucuronide, estradiol, and sex hormone-binding globulin (SHBG) for 3,043 cases and 3,478 controls in the Breast and Prostate Cancer Cohort Consortium. After allowing for multiple testing, none of the SNPs examined were significantly associated with growth factor or hormone concentrations, and the SNP-prostate cancer associations did not differ by these concentrations, although 4 interactions were marginally significant (MSMB-rs10993994 with androstenedione (uncorrected P = 0.008); CTBP2-rs4962416 with IGFBP-3 (uncorrected P = 0.003); 11q13.2-rs12418451 with IGF-1 (uncorrected P = 0.006); and 11q13.2-rs10896449 with SHBG (uncorrected P = 0.005)). The authors found no strong evidence that associations between GWAS-identified SNPs and prostate cancer are modified by circulating concentrations of IGF-1, sex hormones, or their major binding proteins.     

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.     

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.     

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.     

Body size in early life and adult levels of insulin-like growth factor 1 and insulin-like growth factor binding protein 3

Body size in early life has been associated with breast cancer risk. This may be partly mediated through the insulin-like growth factor (IGF) pathway. The authors assessed whether birth weight, body fatness at ages 5 and 10 years, and body mass index (BMI; weight (kg)/height (m)(2)) at age 18 years were associated with plasma concentrations of insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 in 6,520 women aged 32-70 years at blood draw from the Nurses' Health Study (1990-2006) and Nurses' Health Study II (1997-2005). Birth weight, body fatness in childhood, and BMI at age 18 years were inversely associated with adult IGF-1 levels. For example, IGF-1 levels were 11.9% lower in women who reported being heaviest at age 10 years than in those who were leanest at age 10 (P-trend < 0.0001). Further, women who reported their birth weight as ≥10 pounds (≥4.5 kg) (vs. <5.5 pounds (<2.5 kg)) had 7.9% lower IGF-1 levels (P-trend = 0.002). Women whose BMI at age 18 years was ≥30 (vs. <20) had 14.1% lower IGF-1 levels (P-trend < 0.0001). Similar inverse associations were observed for insulin-like growth factor binding protein 3. These observations did not vary by adult BMI or menopausal status at blood draw. These findings suggest that altered IGF-1 levels in adulthood may be a mechanism through which early-life body size influences subsequent breast cancer risk.     

Dietary soy and fats in relation to serum insulin-like growth factor-1 and insulin-like growth factor-binding protein-3 levels in premenopausal Japanese women

Circulating levels of insulin-like growth factor-1 (IGF-1) and insulin-like growth factor-binding protein-3 (IGFBP-3) have each been associated with premenopausal breast cancer risks. We analyzed data from a cross-sectional study of 261 premenopausal Japanese women aged 20-54 yr with adequate nutritional status to evaluate the relationships between concentrations of IGF-1 and IGFBP-3 in serum and dietary intakes of soy, fats and other nutrients. Diet was assessed by a semiquantitative food frequency questionnaire. There was no significant correlation between soy product as well as soy isoflavone intake and serum IGF-1 or IGFBP-3 levels after controlling for age, total energy, percent body fat, and education level. Total fat intake was significantly inversely correlated with serum IGFBP-3 level (r = -0.13, P = 0.04). The correlations of saturated and monounsaturated fats with serum IGFBP-3 were of borderline significance (r = -0.12, P = 0.06 and r = -0.11, P = 0.07, respectively).     

Maternal concentrations of insulin-like growth factor I and insulin-like growth factor binding protein 1 during pregnancy and birth weight of offspring

Maternal concentrations of insulin-like growth factor I (IGF-I) and insulin-like growth factor binding protein 1 (IGFBP-1) may influence fetal growth. Offspring birth weight related to maternal IGF-I and IGFBP-1 measured in pregnancy was studied in 368 randomly selected women without preeclampsia who delivered a singleton liveborn child in Norway between 1992 and 1994. Maternal IGF-I concentrations were not consistently associated with birth weight, but a 1-standard deviation stronger increase in IGF-I from the first to second trimester was associated with an 82-g (95% confidence interval (CI): 11, 153) higher birth weight. IGFBP-1 concentrations were inversely associated with birth weight: Birth weight was 71 g (95% CI: 14, 128) lower per 1-standard deviation higher IGFBP-1 in the second trimester, and an increase in IGFBP-1 from the first (below median) to second (above median) trimester was associated with a 342-g (95% CI: 124, 560) lower birth weight, compared with having low IGFBP-1 (below median) in both trimesters. Conversely, low IGFBP-1 in both trimesters was associated with a 200-350-g higher birth weight compared with other combinations of IGFBP-1. In conclusion, persistently low IGFBP-1 in pregnancy is associated with relatively higher birth weight. Maternal insulin resistance may provide a link between IGFBP-1 and offspring birth weight.     

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。     

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。     

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。     

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。     

Genetic variability in IGF-1 and IGFBP-3 and body size in early life

ABSTRACT: BACKGROUND: Early life body size and circulating levels of IGF-1 and IGFBP-3 have been linked to increased risks of breast and other cancers, but it is unclear whether these exposures act through a common mechanism. Previous studies have examined the role of IGF-1 and IGFBP-3 genetic variation in relation to adult height and body size, but few studies have examined associations with birthweight and childhood size. METHODS: We examined whether htSNPs in IGF-1 and the IGFBP-1/IGFBP-3 gene region are associated with the self-reported outcomes of birthweight, body fatness at ages 5 and 10, and body mass index (BMI) at age 18 among healthy women from the Nurses' Health Study (NHS) and NHSII. We used ordinal logistic regression to model odds ratios (ORs) and 95% confidence intervals (CI) of a one category increase for birthweight and somatotypes at ages 5 and 10. We used linear regression to model associations with BMI at age 18. RESULTS: Among 4567 healthy women in NHS and NHSII, we observed no association between common IGF-1 or IGFBP-1/IGFBP-3 SNPs and birthweight, body fatness at ages 5 and 10, or BMI at age 18. CONCLUSIONS: Common IGF-1 and IGFBP-1/IGFBP-3 SNPs are not associated with body size in early life.     

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.     

Markers of fetal growth and serum levels of insulin-like growth factor (IGF) I, -II and IGF binding protein 3 in adults

Fetal growth has been linked with increased risk of cancer and cardiovascular disease later in life. The insulin-like growth factor (IGF) axis has recently been proposed as a predictor of risk of subsequent cancer and cardiovascular disease. However, only few data are available on the possible association between fetal growth and levels of IGFs later in life. We examined the association between markers of fetal growth, i.e. birth weight, birth length and Ponderal Index, from birth records and serum IGF-I, IGF-II, and IGF binding protein 3 (IGFBP-3) levels in 545 middle-aged Danish men and women. We fitted separate multivariate models including birth weight, birth length, Ponderal Index and serum IGF-I, IGF-II, and IGFBP-3, respectively. After adjustment for age, alcohol intake, smoking, diabetes mellitus, systolic and diastolic blood pressure, serum total cholesterol and current height and weight, we found negative associations between birth weight and Ponderal Index, respectively, and serum IGF-II in men, i.e. the mean regression coefficients were -49.41 (95% CI: -87.06-11.77) (microg/l)/kg and -3.49 (95% CI: -6.73-0.25) (microg/l)/(kg/m3), respectively. Furthermore, in men birth weight was negatively associated with the (IGF-I + IGF-II)/IGFBP-3 and IGF-II/IGFBP-3 ratios, which are believed to be indicators of bioavailable IGF and IGF-II, respectively. However, no other associations were found in any of the models. Between 1 and 16% of the variance in serum IGF-I, IGF-II, and IGFBP-3, respectively, could be explained by the statistical models used in the analyses. We found very little support to the hypothesis of an association between fetal growth and the IGF axis throughout life.     

Isolated isoflavones do not affect the circulating insulin-like growth factor system in men at increased colorectal cancer risk

Epidemiological studies show that increased insulin-like growth factor (IGF)-I concentrations are related to increased colorectal cancer risk. A reduced colorectal cancer risk has been associated with isoflavones, which might affect the IGF-system because of their weak estrogenic activity. We conducted a randomized, placebo-controlled, double-blind crossover study to investigate the effect of an 8-wk isolated isoflavone supplementation (84 mg/d) on serum concentrations of total IGF-I, free IGF-I, total IGF-II, IGF binding protein (BP)-1, IGFBP-2, and IGFBP-3. Additionally, we investigated whether IGF-system component differences were related to concentrations of the more potent estrogenic isoflavone metabolite, equol. Our study population consisted of 37 men with a family history of colorectal cancer or a personal history of colorectal adenomas. Isoflavone supplementation did not significantly affect serum total IGF-I concentrations (relative difference between serum total IGF-I concentrations after isoflavone supplementation and after placebo: -1.3%, 95% CI -8.6 to 6.0%). Neither free IGF-I, nor total IGF-II, IGFBP-1, IGFBP-2, or IGFBP-3 concentrations were significantly altered. Interestingly, the change in serum IGF-I concentrations after isoflavone supplementation was negatively associated with serum equol concentrations (r=-0.49, P=0.002). In conclusion, isolated isoflavones did not affect the circulating IGF-system in a male high-risk population for colorectal cancer. However, to our knowledge, this is the first study that suggests isoflavones might have an IGF-I lowering effect in equol producers only. This underlines the importance of taking into account equol status in future isoflavone intervention studies.     

Anthropometric and behavioral correlates of insulin-like growth factor I and insulin-like growth factor binding protein 3 in middle-aged Japanese men

High levels of plasma insulin-like growth factor I (IGF-I) and low levels of insulin-like growth factor binding protein 3 (IGFBP-3) have been related to increased risk of several cancers. Little is known about the behavioral determinants of these biologic markers. The authors examined the relation of anthropometric and behavioral factors to plasma concentrations of IGF-I and IGFBP-3 in a cross-sectional study of 616 Japanese men aged 45-55 years in 1995-1996. In univariate analyses, body mass index was strongly, positively associated with both IGF-I and IGFBP-3. The waist/hip ratio was also linearly related to IGF-I and IGFBP-3 up to the third quartile level. Height was weakly, positively associated with IGF-I and IGFBP-3. Smoking was inversely associated with IGF-I and IGFBP-3. Alcohol use was associated inversely with IGF-I and positively with IGFBP-3. Neither IGF-I nor IGFBP-3 was related to physical activity. Results of the multivariate analysis were essentially the same as those of the univariate analyses. The findings regarding body mass index are in contrast to those of previous studies showing null or inverse associations, and they suggest that the relation of body mass index to IGF-I or IGFBP-3 may vary among populations. The study also indicates that smoking and alcohol use might affect plasma IGF-I and IGFBP-3.     

A potential inverse association between insulin-like growth factor I and hypertension in a cross-sectional study

PURPOSE: Elevated circulating insulin-like growth factor I (IGF-I) levels increasingly are being implicated as a potential risk factor for the development of some cancers; however, relatively few epidemiologic studies have focused on potential relationships between circulating IGF-I levels and cardiovascular risk factors or cardiovascular disease. Hence, our objective is to examine relationships between IGF-I levels; body mass index (BMI); fasting insulin level; IGF binding protein 1 (IGFBP-1), IGFBP-2, and IGFBP-3 levels; and an array of traditional cardiovascular risk factors. METHODS: Our analysis included 715 men and women aged 30 to 62 years who participated in the V?sterbotten Intervention Project cohort. IGF-I and IGFBP-1, -2, and -3 were measured in stored plasma samples. Cardiovascular risk factors of interest included glucose level (fasting and 2-hour postload), lipid levels (total cholesterol, high-density lipoprotein cholesterol, and triglycerides), blood pressure (systolic and diastolic), and hypertension status. All presented results were adjusted for age, sex, and laboratory batch. RESULTS: IGF-I quartile was associated inversely with 2-hour glucose level and diastolic blood pressure. There was a stepwise inverse graded association between increasing IGF-I quartile and hypertension, with an odds ratio of 0.51 (95% confidence interval, 0.29-0.90) for hypertension comparing the fourth IGF-I quartile with the first. Further adjusting for BMI and IGFBP-3 level simultaneously strengthened the inverse association, with an odds ratio of 0.42 (95% confidence interval, 0.22-0.80) for hypertension comparing the fourth with the first IGF-I quartile. CONCLUSIONS: Contrary to positive associations between IGF-I levels and some cancers, our results suggest that IGF-I level may be related inversely to prevalent hypertension, a risk factor for cardiovascular disease.     

Serum insulin-like growth factor I and subsequent risk of colorectal cancer among Japanese-American men

Recent reports suggest that colorectal cancer is positively related to insulin-like growth factor I (IGF-I) and inversely related to insulin-like growth factor binding protein 3 (IGFBP-3). To evaluate these associations further and separately for colon and rectal cancer, the authors conducted a nested case-control study in a cohort of 9,345 Japanese-American men examined in Hawaii in 1971-1977. A total of 177 incident colon cancer cases and 105 incident rectal cancer cases were identified from 1972 to 1996. These patients' stored sera and those of 282 age-matched controls were measured for IGF-I and IGFBP-3. The adjusted mean level of IGF-I was higher in colon cancer cases than in controls (154.7 ng/ml vs. 144.4 ng/ml; p = 0.01). However, the multivariate odds ratio for the highest quartile compared with the lowest was just 1.8 (95% confidence interval: 0.8, 4.3). Adjusted mean IGF-I levels were similar between rectal cancer cases and their controls. For IGFBP-3, adjusted mean levels were lower for both colon and rectal cancer cases than for their matched controls, but the differences were not significant. The IGF-I results weakly support findings from other studies and suggest that there are differences in IGF-I findings between colon and rectal cancer cases. It is possible that IGF-related risk is confounded by other factors that may vary among different cohorts. Further research is needed to clarify these relations.