Insulin-like growth factor I (IGF-I) serum level modifications during transdermal estradiol treatment in postmenopausal women: a possible bimodal effect depending on basal IGF-I values

Oral contraceptives and colorectal cancer risk - A meta-analysis and systematic review

There is limited understanding of the potential relationship between the risk of colorectal cancer and oral contraceptive use among women of different ages. Further investigation on the issue helps develop an informed choice of contraception. Data for this meta-analysis were derived from case-control and cohort studies of colorectal cancer and oral contraceptive use conducted between June 2000 and May 2022. The studies had a very high heterogeneity, as shown by an I² of 99%, and a confidence interval of 95% was considered significant. Other results from the meta-analysis were as follows; Heterogeneity: Chi² = 585.13, df = 6 (P < 0.00001). A test of the overall effect of ever use versus never use of oral contraceptives was Z = 21.85 (P < 0.00001). All the studies had a pooled risk ratio (RR) of 0.53. The use of oral contraceptives is associated with reduced risk of developing colorectal cancer. There is a need for further research into the biological mechanisms underlying these relationships, which may lead to insights into potential preventive interventions for colorectal carcinogenesis in women. The keywords used to locate studies included in this meta-analysis include Keywords targeting oral contraceptives included oral contraceptive pills, and birth control pills. Search keywords targeting colorectal carcinogenesis included neoplasms, tumors, or colon and rectal cancer.

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Oral contraceptive use in woman does affect the risk of developing colorectal cancer.

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Colorectal cancer has many identifiable and nonidentifiable risk factors.

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OCP usage in women of various age groups shown a lower risk of colorectal cancer development than those who never used OCPs.

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Regarding the population at risk for colorectal cancer due to a variety of reasons, many studies have deemed OCP usage safe.

A summary of the influence of exogenous estrogen administration across the lifespan on the GH/IGF-1 axis and implications for bone health

Bone growth, development, and remodeling are modulated by numerous circulating hormones. Throughout the lifespan, the extent to which each of the hormones impacts bone differs. Understanding the independent and combined impact of these hormones on controlling bone remodeling allows for the development of more informed decision making regarding pharmacology, specifically the use of hormonal medication, at all ages. Endocrine control of bone health in women is largely dictated by the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis and the hypothalamic-pituitary-ovarian (HPO) axis. Growth hormone, secreted from the pituitary gland, stimulates cells in almost every tissue to secrete IGF-1, although the majority of circulating IGF-1 is produced hepatically. Indeed, systemic IGF-1 concentrations have been found to be correlated with bone mineral density (BMD) in both pre- and post-menopausal women and is often used as a marker of bone formation. Sex steroids produced by the ovaries, namely estradiol, mediate bone resorption through binding to estrogen receptors on osteoclasts and osteoblasts. Specifically, by increasing osteoclast apoptosis and decreasing osteoblast apoptosis, adequate estrogen levels prevent excessive bone resorption, which helps to explain the rapid decline in bone mass that occurs with the menopausal decrease in estrogen production. Though there are documented correlations between endogenous estrogen concentrations and GH/IGF-1 dynamics, this relationship changes across the lifespan as sex-steroid dynamics fluctuate and, possibly, as tissue responsiveness to GH stimulation decreases. Aside from the known role of endogenous sex steroids on bone health, the impact of exogenous estrogen administration is of interest, as exogenous formulations further modulate GH and IGF-1 production. However, the effect and extent of GH and IGF-1 modulation seems to be largely dependent on age at administration and route of administration. Specifically, premenopausal women using combined oral contraceptive therapy (COC), post-menopausal women taking oral hormone therapy (HT), and both pre- and post-menopausal women using a transdermal form of estrogen therapy (COC or HT) demonstrate disparate GH/IGF-1 responses to exogenous estrogen. This review serves to summarize what is currently known regarding the influence of exogenous estrogen administration across the lifespan on the GH/IGF-1 axis and implications for bone health.

Hormone replacement therapy, oral contraceptive use, and distal large bowel cancer: a population-based case-control study

OBJECTIVES

Lower incidence rates of distal large bowel cancer in women when compared with men support the protective role of female hormones. We aimed to determine the associations between hormone replacement therapy, oral contraceptive use, and distal large bowel cancer.

METHODS

We conducted a population-based case-control study of incident distal large bowel cancer in North Carolina between 2001 and 2006. Data on hormone replacement therapy, oral contraceptive use, demographics, and risk factors were obtained through in-person interviews. Odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between oral contraceptive use, hormone replacement therapy, and distal large bowel cancer were estimated through unconditional logistic regression models overall, by duration of use, and within strata of race.

RESULTS

There were a total of 443 women with distal large bowel cancer and 405 controls. Ever use of hormone replacement therapy was strongly associated with a reduced risk of distal large bowel cancer (OR 0.52, 95% CI 0.38-0.72). Further reduction of distal large bowel cancer risk occurred with increased duration of use (<4 years (OR 0.77, 95% CI 0.44-1.35), 4-8 years (OR 0.64, 95% CI 0.37-1.10), 9-14 years (OR 0.47, 95% CI 0.27-0.81), and >or=15 years (OR 0.34, 95% CI 0.20-0.58)). Ever use of oral contraceptives was not associated with reduced incidence of distal large bowel cancer (OR 0.95, 95% CI 0.67-1.34) nor was duration of use. There were no differences by race.

CONCLUSIONS

Hormone replacement therapy is associated with a lower risk of distal large bowel cancer. This risk is further reduced with increased duration of use. Hormone replacement therapy may be partially responsible for the reduced incidence of distal large bowel cancer in women compared with men.

Differential effects of various progestogens on metabolic risk factors for breast cancer

Biological and epidemiological findings suggest that metabolic factors - insulin, insulin-like growth factor-I (IGF-I) and sex hormone-binding globulin (SHBG) - are involved in the development and promotion of breast cancer. Estrogens, particularly if administered orally, counteract metabolic factors that increase breast cancer risk, i.e. they reduce insulin and IGF-I and increase SHBG. This could contribute toward explaining epidemiological data showing that unopposed oral estrogens do not increase breast cancer risk, or do so only modestly. In contrast to natural progesterone and progesterone-derived progestins, progestins endowed with androgenic (or glucocorticoid) activity negatively influence these metabolic factors, counteracting the favorable effects of estrogens. While most biological and epidemiological findings suggest that natural progesterone does not augment breast cancer risk, available data show an increased risk with synthetic progestins - with the possible exception of progesterone-derived dydrogesterone. Different mechanisms for different progestins could possibly be involved. Differences from progesterone with regard to pharmacokinetics and pharmacodynamics, potency, interaction with the two isoforms of the progesterone receptor, and binding to other steroid receptors could all be relevant. These remain theoretical speculations for the time being, but the possibility that some progestins increase breast cancer risk through their negative influence on metabolic factors cannot be rejected.

High serum IGFBP-2 is predictive of increased bone turnover in aging men and women

Elevated serum IGFBP-2 is associated with lower BMD in men and women. It is unknown whether IGFBP-2 serves as a negative regulator of bone metabolism by decreasing bone formation or increasing bone resorption. Studying an age-stratified community-based sample of 344 men and 276 women, IGFBP-2 was the strongest predictor of increased bone resorption among the IGF/IGFBPs studied.

INTRODUCTION

Serum insulin-like growth factor binding protein-2 (IGFBP-2), which increases with age, is a predictor of low BMD among aging men and women. However, it is unknown whether IGFBP-2 negatively influences bone metabolism by decreasing bone formation or increasing bone resorption. Few have examined the relation between the insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) with bone turnover markers.

MATERIALS AND METHODS

In an age-stratified, random sample of the community, we examined the association between serum IGF-I, IGF-II, IGFBP-1, -2, and -3, and bone turnover markers before and after adjustment for potential confounders (age, body mass index, bioavailable estradiol and testosterone, and sex hormone binding globulin). Analyses were stratified by sex and menopausal status.

RESULTS

We studied 344 men (age range, 23-90 yr) and 276 women (age range, 21-93 yr; 166 postmenopausal) not on oral contraceptives or hormone replacement. Among the IGF/IGFBPs assessed, IGFBP-2 was the strongest and most consistent predictor of bone turnover in men and women. After adjustment for potential confounders, IGFBP-2 was positively associated with osteocalcin (OC) and urine and serum N-teleopeptide (NTX) in men (r = 0.20, 0.26, and 0.23, respectively; p < 0.001), serum C-telopeptide (CTX) in premenopausal women (r = 0.28; p < 0.01), and OC, urine NTX, and serum CTX in postmenopausal women (r = 0.24, 0.33, and 0.19, respectively; p < 0.05).

CONCLUSIONS

Higher serum IGFBP-2, which is predictive of lower BMD, is associated with increased markers of bone resorption, independent of age, body mass, and sex hormones. The association between IGFBP-2 and markers of bone formation may reflect coupling with increased bone resorption, which is not adequate to maintain BMD.

Direct effects of sex steroid hormones on adipose tissues and obesity

Sex steroid hormones are involved in the metabolism, accumulation and distribution of adipose tissues. It is now known that oestrogen receptor, progesterone receptor and androgen receptor exist in adipose tissues, so their actions could be direct. Sex steroid hormones carry out their function in adipose tissues by both genomic and nongenomic mechanisms. In the genomic mechanism, the sex steroid hormone binds to its receptor and the steroid-receptor complex regulates the transcription of given genes. Leptin and lipoprotein lipase are two key proteins in adipose tissues that are regulated by transcriptional control with sex steroid hormones. In the nongenomic mechanism, the sex steroid hormone binds to its receptor in the plasma membrane, and second messengers are formed. This involves both the cAMP cascade and the phosphoinositide cascade. Activation of the cAMP cascade by sex steroid hormones would activate hormone-sensitive lipase leading to lipolysis in adipose tissues. In the phosphoinositide cascade, diacylglycerol and inositol 1,4,5-trisphosphate are formed as second messengers ultimately causing the activation of protein kinase C. Their activation appears to be involved in the control of preadipocyte proliferation and differentiation. In the presence of sex steroid hormones, a normal distribution of body fat exists, but with a decrease in sex steroid hormones, as occurs with ageing or gonadectomy, there is a tendency to increase central obesity, a major risk for cardiovascular disease, type 2 diabetes and certain cancers. Because sex steroid hormones regulate the amount and distribution of adipose tissues, they or adipose tissue-specific selective receptor modulators might be used to ameliorate obesity. In fact, hormone replacement therapy in postmenopausal women and testosterone replacement therapy in older men appear to reduce the degree of central obesity. However, these therapies have numerous side effects limiting their use, and selective receptor modulators of sex steroid hormones are needed that are more specific for adipose tissues with fewer side effects.

A potentially deleterious role of IGFBP-2 on bone density in aging men and women

The role of the IGFs and IGFBPs on age-related changes in BMD in adult men and women is not well understood. Studying an age-stratified community based sample of 344 men and 276 women, we found higher IGFBP-2 levels to be associated with lower BMD. IGFBP-2, which increases with age in both men and women, was the strongest, most consistent predictor of BMD among the IGF/IGFBPs studied.

INTRODUCTION

Insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) are important regulators of tissue growth and metabolism, but their association with BMD in adult men and women is controversial.

MATERIALS AND METHODS

In an age-stratified, random sample of the community population, we examined the role of serum levels of IGF-I, IGF-II, and IGFBP-1, -2, and -3 on BMD of the proximal femur (total hip), lateral spine, midshaft, and ultradistal radius as measured by DXA. We explored the association before and after adjustment for potential confounders, including age, bioavailable estradiol and testosterone, sex hormone binding globulin (SHBG), and measures of total fat and skeletal muscle mass.

RESULTS

We studied 344 men (age, 23-90 years) and 276 women (age, 21-93 years; 166 postmenopausal) not on hormone replacement or oral contraceptives. In both men and women, IGF-I and IGFBP-3 levels fell with advancing age, whereas IGFBP-2 levels tended to rise with age. There was an inverse association of IGFBP-2 with BMD at most skeletal sites in men and both premenopausal and postmenopausal women, whereas lower IGF-I and IGFBP-3 were associated with lower BMD in men and postmenopausal women only. Lower IGF-II was associated with lower BMD in men only. There were no associations between IGFBP-1 and BMD in either sex. After adjustment for age, in most cases, we found no further associations between IGF-I, IGF-II, or IGFBP-3 and BMD. In contrast, after age adjustment, higher IGFBP-2 remained a predictor of lower BMD in men and postmenopausal women at all sites except for the lateral spine (for men: r = -0.21, -0.20, and -0.19, all p < 0.001; and for postmenopausal women: r = -0.34, -0.24, and -0.25, all p < 0.01, for the total hip, midshaft, and ultradistal radius, respectively). IGFBP-2 remained an independent negative predictor of BMD in men, postmenopausal women, and all women combined after additional adjustment for bioavailable sex steroids, but not at all sites after adjustment for SHBG and muscle mass. In premenopausal women, IGFBP-2 had similar associations as seen in postmenopausal women, but they were weaker and not statistically robust.

CONCLUSIONS

Among the IGF/IGFBPs in our study, IGFBP-2 was a key negative predictor of BMD among men and women, particularly postmenopausal women. Our findings suggest a potential role of the IGF/IGFBP system in regulating bone loss in aging men and women and identify a previously under-recognized, potentially deleterious role for IGFBP-2, a known inhibitor of IGF action that increases with age in both sexes. Whether the action of the IGF/IGFBP system on bone metabolism is mediated partly through its effects on muscle mass or SHBG deserves further study.

Differential effects of progestins on the circulating IGF-I system

OBJECTIVE

Circulating insulin-like growth factor-I (IGF-I) is mainly produced by the liver under GH stimulation and is influenced by nutrition and insulin. IGF-I bioavailability is regulated by interactions with specific binding proteins (IGFBPs). The objective of this paper is to review available data on modifications of the IGF-I system in menopausal women during HRT, with particular attention on the differential effects of progestins.

METHOD

All available reports on the effects of different forms of HRT have been taken into account.

RESULTS

Available data suggest that different kinds of HRT have different effect on the IGF-I system, depending on route of administration, oestrogen dose, basal IGF-I values and type of progestin. Oestrogen administration (oestrogen replacement therapy (ERT)) reduces circulating IGF-I mainly through a hepatocellular effect. The decrease is sharper when oral ERT is used (first pass hepatic effect) and in women with higher basal IGF-I levels. The progestins endowed with androgenic effects--the 19-nortestosterone derivatives and, to a lesser extent, medroxyprogesterone acetate (MPA)--tend to reverse the IGF-I decrease induced by oral oestrogens. In contrast, progestins devoid of androgen-like hepatocellular and metabolic actions (e.g. dydrogesterone) do not interfere with the IGF-I decrease induced by oral oestrogens. Data on the effect of ERT on IGFBP-3 level are not consistent. Oral ERT, via hepatocellular actions (amplified by the first pass hepatic effect) causes a two to three-fold increase in IGFBP-1 levels. Androgenic progestins oppose the IGFBP-1 increase induced by oral oestrogens. Data on the effect of ERT and different progestins on the level of free IGF-I are scant and inconsistent.

CONCLUSION

Even if some aspects need clarification, available data demonstrate that different progestins have differential effects on the circulating IGF-I system.

Hormone replacement therapy and cancer risk: a systematic analysis from a network of case-control studies

To provide comprehensive and quantitative information on the benefits and risks of hormone replacement therapy (HRT) on several cancer sites, we systematically examined the relation between HRT use and the risk of various cancers in women aged 45-79 by using data from a framework of case-control studies conducted in Italy between 1983 and 1999. The overall data set included the following incident, histologically confirmed neoplasms: oral cavity, pharynx, larynx and esophagus (n = 253), stomach (n = 258), colon (n = 886), rectum (n = 488), liver (n = 105), gallbladder (n = 31), pancreas (n = 122), breast (n = 4,713), endometrium (n = 704), ovary (n = 1,614), urinary bladder (n = 106), kidney (n = 102), thyroid (n = 65), Hodgkin's disease (n = 26), non-Hodgkin's lymphomas (n = 145), multiple myeloma (n = 65) and sarcomas (n = 78). The control group comprised 6,976 women aged 45-79 years, admitted for a wide spectrum of acute, nonneoplastic conditions. Odds ratios (OR) and the corresponding 95% confidence intervals (CI) for use of HRT were derived from multiple logistic regression equations. There was an inverse association between ever use of HRT and colon (OR = 0.7), rectum (OR = 0.5) and liver cancer (OR = 0.2), with a consistent pattern of protection for duration of use. An excess risk was found for gallbladder (OR = 3.2), breast (OR = 1.1), endometrial (OR = 3.0) and urinary bladder cancer (OR = 2.0). These data from a southern European population add some useful information on the risk-benefit assessment of HRT among postmenopausal women.

Oral contraceptives and colorectal cancer

BACKGROUND

Only limited information and understanding are available on the potential relation between oral contraceptive use and the risk of colorectal cancer. Further data on the issue are therefore useful and may help informed choice of contraception.

METHODS AND RESULTS

Data were derived from a case-control study of colorectal cancer conducted between 1992 and 2001 in the Swiss Canton of Vaud, including 131 women with colorectal cancer and 373 controls admitted in the same hospital as the cases with diagnosis of acute, non-neoplastic disease, unrelated to long-term modification of diet. Oral contraceptive use was reported by 11% of cases versus 17% of controls, corresponding to multivariate odds ratio of 0.8 (95% CI: 0.4-1.7). The odds ratio was non-significantly below unity across strata of duration, time since first and last oral contraceptive use.

CONCLUSION

These findings add further evidence on a possible inverse relation between oral contraceptive and colorectal cancer risk.

Positive effects on cardiovascular and breast metabolic markers of oral estradiol and dydrogesterone in comparison with transdermal estradiol and norethisterone acetate

OBJECTIVES

To assess differences in two sequential combined hormone replacement therapy (HRT) products on selected cardiovascular and breast metabolic markers. The products were different concerning the route of administration of estradiol and its combined progestin, either oral or transdermal, and the androgenic properties of progestogens, respectively, dydrogesterone and norethisterone acetate.

METHODS

One hundred and nineteen healthy non-hysterectomized postmenopausal women were included in this open, multi-center, two parallel group trial. They were randomized to a treatment of six 28-day cycles with oral estradiol sequentially combined with dydrogesterone (oE2/D10) or a sequential combination patch of estradiol plus norethisterone acetate (tdE/NETA). At baseline and after six cycles the high-density lipoprotein cholesterol (HDL-C), the sex hormone binding globulin (SHBG) and the total insulin-like growth factor-I (IGF-I) blood levels were determined by a central laboratory. A total of 89 women were compliant to the protocol.

RESULTS

After six cycles, a statistically significant difference (P<0.001) concerning HDL-C, SHBG and IGF-I levels was found between the two treatment groups. The HDL-C levels were increased in the oE2/D10 group and decreased in the tdE/NETA group, with a final difference of about 0.3 mmol/l. The oE2/D10 treatment induced a sharp increase (about 57 mmol/l) in SHBG levels. IGF-I levels decreased with both the products, but the difference in favor of the oE2/D10 treatment was of about 30 ng/ml. Moreover, patients on tdE/NETA with an IGF-I baseline value below the median showed an increase.

CONCLUSION

Oral estradiol sequentially combined with dydrogesterone, a non-androgenic progestogen, induced positive changes of some cardiovascular (HDL-C) and breast (SHBG and IGF-I) metabolic markers. These effects were significantly different from those obtained with a transdermal estradiol associated to an androgenic progestogen.

IGF-1 in gynaecology and obstetrics: update 2002

Recent discoveries on endocrine, paracrine and autocrine involvement of insulin-like growth factor-1 (IGF-1) in the proliferation of many tissues raised the attention of its role in reproduction and in the growth of various cancers as well as of benign proliferations. The intention of this article is to focus on IGF-1 in the field of gynaecology. Perimenopausal women who exhibit high IGF-1 and low IGF binding protein (IGFBP) levels, like IGFBG-3, have an increased risk of developing breast cancer. A higher risk for cervical, ovarian and endometrial cancer is related to high IGF-1 levels in post- and premenopausal women. It has been shown that myomas, by far the most common benign uterine tumor in women, grow in the presence of IGF-1, in vitro as well as in vivo. Studies show that IGF-1 is involved in the differentiation of various reproductive tissues, like endometrium and ovarian tissues. Patients suffering from polycystic ovary syndrome (PCO) frequently show insulin resistance accompanied by an increase of IGF-1 in plasma. Plasma IGF-1 levels are higher in cases of severe endometriosis, however, in endometriosis and in PCO IGF levels locally in the endometrium are reduced, what might explain infertility. Recently, it was shown that IGF facilitates the implantation of the human embryo in the endometrium during IVF. Implantation is a paradox where different immune systems have to collaborate to make implantation and survival of the pregnancy possible. IGF seems to be the starter molecule so that the two epithelia can fuse. A disturbance can result in complications during pregnancy i.e. spontaneous miscarriage, preeclampsia as well as defects of the embryo. Therefore, IGF is a useful marker in successful pregnancy as well. A better mechanistic understanding of IGF-1 action on the cellular level not only provides more elegant mechanistic explanations for the scientist, but the practitioner might find it interesting to utilize its diagnostic potential as a marker for various diseases. The relation between systemic IGF levels and local tissue IGF-1 levels has not yet been determined for all conditions.

Pathologic and biological prognostic factors of breast cancers in short- and long-term hormone replacement therapy users

BACKGROUND

Breast cancer tumors occurring in hormone replacement therapy (HRT) users are less aggressive, but no studies have compared tumor aggressiveness among HRT users by length and mode of therapy.

METHODS

A total of 1105 consecutive postmenopausal patients treated for operable breast cancer at the European Institute of Oncology were identified. Women exposed to HRT were compared with HRT nonusers by clinical stage at presentation and pathologic and biological tumor characteristics. HRT duration and administration modality were analyzed in relation to tumor characteristics in the HRT group.

RESULTS

Better stage distribution, including smaller pathologic tumor diameter and fewer involved axillary lymph nodes, was seen in the HRT group. Estrogen receptor-positive tumors were more frequent in the control group, but this tendency was reversed with longer exposure to HRT. Histological grade III tumors were less frequent in the HRT group. More favorable prognostic factors were associated with HRT >5 years. The proliferative fraction was higher in patients with exposure <1 vs. >5 years and in oral versus transdermal users.

CONCLUSIONS

Breast cancers developing during HRT have better prognostic characteristics than those seen in HRT nonusers. A trend toward better prognostic characteristics with increasing duration of HRT was seen.

Oral contraceptives and cancer: an update

Most up-to-date information on oral contraceptives (OCs) and breast cancer risk comes from a collaborative re-analysis of individual data on 53297 cases and 100239 controls. It is now established that there is a moderately increased breast cancer risk among current OC users, which tends to level off in the few years after stopping use. With regard to cervical cancer, OC use has been found to be associated with increased risk in human papilloma virus-positive women. With reference to the well known protective effects of OCs against endometrial carcinogenesis, additional information has suggested a consistent protection across types of OCs used. Further data on ovarian cancer confirm that the protection of OCs is long lasting, and may well be observed 15 to 20 years after stopping use. Several studies have suggested an inverse relationship between use of OCs and risk of colorectal cancer, and in a meta-analysis of published data the pooled relative risk of colorectal cancer for DC ever-use was 0.82 (95% confidence interval 0.74 to 0.97). There was no association with duration of use. The increased risk for hepatocellular carcinoma in the absence of hepatitis B viruses is the only established evidence of a direct association between OC use and cancer risk, which led an International Agency for Research on Cancer Working Group to classify OCs as carcinogenic to humans in 1998.

Oral contraceptives and colorectal cancer risk: a meta-analysis

Several studies have suggested an inverse association between use of combined oral contraceptives (OC) and the risk of colorectal cancer and here we present a meta-analysis of published studies. Articles considered were epidemiological studies published as full papers in English up to June 2000 that included quantitative information on OC use. The pooled relative risks (RR) of colorectal cancer for ever OC use from the 8 case-control studies was 0.81 (95% confidence interval (CI): 0.69-0.94), and the pooled estimate from the 4 cohort studies was 0.84 (95% CI: 0.72-0.97). The pooled estimate from all studies combined was 0.82 (95% CI: 0.74-0.92), without apparent heterogeneity. Duration of use was not associated with a decrease in risk, but there was some indication that the apparent protection was stronger for women who had used OCs more recently (RR = 0.46; 95% CI: 0.30-0.71). A better understanding of this potential relation may help informed choice of contraception.

Effects of two oral contraceptives on plasma levels of insulin-like growth factor I (IGF-I) and growth hormone (hGH)

In 18 healthy women, the effect of two oral contraceptives (OCs) on insulin-like growth factor (IGF-I) and its binding protein-3 (IGFBP-3) and growth hormone (hGH) plasma level were studied before and after intake of either of two OC formulations over 21 days, one containing 2 mg dienogest and 0.03 mg ethinylestradiol (group A) and the other 0.125 mg levonorgestrel and 0.03 mg ethinylestradiol (group B). There was a reduction of the mean IGF-I concentration of 30% (p = 0.008) in the women receiving dienogest-containing pills and 12% (p = 0.006) in women taking the levonogestrel-containing preparation. This difference between drug groups was statistically significant (p = 0.002). A correlation between the control values and the basal-treatment difference (r = 0.945; p = 0.000) was observed only in women of group A. Between basal and treatment cycles the mean plasma levels of hGH remained unchanged in both groups tested, but the 23.5-h integrated mean hGH plasma concentrations (AUC(0-23.5h)) were significantly elevated by 36% (p = 0.016) in comparison to basal values before treatment only in women receiving the levonorgestrel-containing pills. Also, in the women who received the dienogest-containing preparation, the changes of integrated mean plasma level were inversely associated with the control values (r = -0.723; p = 0.025). Neither in group A nor in group B was the mean plasma level of IGFB-3 changed.

IN CONCLUSION

the results of the present analysis indicate that hormonal contraceptives can modulate the GH and IGF-I-axis in the reproductive age. Probably the androgenic progestogen levonorgestrel (0.125 mg/day) opposes the estrogen-induced action. In the women who took the dienogest-containing formulations (anti-androgenic progestogen-group A), the extent of individual changes (hGh and IGF-I) depends on the basal level prior to pill intake. Further studies, especially of long-term intake of OCs, are necessary to confirm these results and to assess the practical relevance for possible effects on connective tissue and bone.

HRT and breast cancer risk: a clue for interpreting the available data

Epidemiological and biological data on HRT and breast cancer risk are reviewed. Some aspects deserve consideration. (1) The majority of epidemiological data have been gathered from populations where high estrogen doses (> or = 1.25 mg daily of conjugated estrogens) were used as first line therapy. (2) HRT does not increase the risk in overweight women, even in the series in which a risk increase (in longterm users) is found. This could be as a result of the fact that oral estrogens, through their metabolic and hepatocellular effects, reverse some biological features of obesity (e.g. increased insulin-like growth factor I activity and decreased sex hormone binding globulin level) which potentially increase breast cancer risk, so balancing the estrogen stimulation. (3) The progestin addition seems to increase the risk when the 19 nor-testosterone derivatives are used. These androgenic compounds contrast the metabolic and hepatocellular effects of oral estrogens. To sum up, the possibility does exist that even the longterm use of oral estrogens at the right ('low') dose, with the addition of a non-androgenic progestin, will be shown to be associated with a very limited breast cancer risk increase.