Height, leg length, and cancer risk: a systematic review

Leg length, sitting height and postmenopausal breast cancer risk

Background:

Tallness has consistently been associated with an increased risk of breast cancer. We investigated the association further by decomposing height into leg length and sitting height.

Methods:

From the prospective Danish cohort ‘Diet, Cancer and Health’, 23 864 postmenopausal women enrolled during 1993–1997 were followed for a diagnosis of breast cancer in the Danish Cancer Registry through 2009.

Results:

The incidence rate ratios for breast cancer were 1.11 (95% CI=1.06–1.16) for each 5 cm increase in total height and 1.09 (95% CI=1.01–1.17) and 1.14 (95% CI=1.04–1.25) for each 5 cm increase in leg length and sitting height, respectively. There was no statistical significant difference between the associations for leg length and sitting height (P=0.47).

Conclusion:

Leg length does not seem to be more strongly associated with breast cancer among postmenopausal women than sitting height.

Arm length is associated with type 2 diabetes mellitus in Japanese-Americans

AIMS/HYPOTHESIS

The aim of the study was to examine the association of type 2 diabetes mellitus with arm length as a marker for early life environment and development.

METHODS

This was a cross-sectional analysis of 658 second- and third-generation Japanese-Americans (349 men and 309 women). Different arm length (total, upper and forearm length) and leg length (total and lower leg length) measurements were performed. Type 2 diabetes was defined by the use of hypoglycaemic medication, fasting plasma glucose (FPG) ≥ 7 mmol/l or glucose at 2 h ≥ 11.1 mmol/l during an OGTT. Persons meeting the criteria for impaired glucose tolerance were excluded from these analyses (FPG <7 mmol/l and 2 h glucose during an OGGT <11.1 but ≥ 7.8 mmol/l). Multivariable logistic regression was used to estimate associations between prevalence of diabetes and limb length while adjusting for possible confounders.

RESULTS

A total of 145 individuals had diabetes. On univariate analysis, arm and leg length were not associated with diabetes. After adjustment for age, sex, computed tomography-measured intra-abdominal fat area, height, weight, smoking status and family history of diabetes, total arm length and upper arm length were inversely related to diabetes (OR for a 1 SD increase 0.49, 95% CI 0.29, 0.84 for total arm length, and OR 0.56, 95% CI 0.36, 0.87 for upper arm length). Forearm length, height and leg length were not associated with diabetes after adjustment for confounding variables.

CONCLUSIONS/INTERPRETATION

Our findings of associations between arm lengths and prevalence of type 2 diabetes supports a role for factors that determine bone growth or their correlates in the development of this condition.

Children of low socioeconomic status show accelerated linear growth in early childhood; results from the Generation R Study

OBJECTIVES

People of low socioeconomic status are shorter than those of high socioeconomic status. The first two years of life being critical for height development, we hypothesized that a low socioeconomic status is associated with a slower linear growth in early childhood. We studied maternal educational level (high, mid-high, mid-low, and low) as a measure of socioeconomic status and its association with repeatedly measured height in children aged 0-2 years, and also examined to what extent known determinants of postnatal growth contribute to this association.

METHODS

This study was based on data from 2972 mothers with a Dutch ethnicity, and their children participating in The Generation R Study, a population-based cohort study in Rotterdam, The Netherlands (participation rate 61%). All children were born between April 2002 and January 2006. Height was measured at 2 months (mid-90% range 1.0-3.9), 6 months (mid-90% range 5.6-11.4), 14 months (mid-90% range 13.7-17.9) and 25 months of age (mid-90% range 23.6-29.6).

RESULTS

At 2 months, children in the lowest educational subgroup were shorter than those in the highest (difference: -0.87 cm; 95% CI: -1.16, -0.58). Between 1 and 18 months, they grew faster than their counterparts. By 14 months, children in the lowest educational subgroup were taller than those in the highest (difference at 14 months: 0.40 cm; 95% CI: 0.08,0.72). Adjustment for other determinants of postnatal growth did not explain the taller height. On the contrary, the differences became even larger (difference at 14 months: 0.61 cm; 95% CI: 0.26,0.95; and at 25 months: 1.00 cm; 95% CI: 0.57,1.43)

CONCLUSIONS

Compared with children of high socioeconomic status, those of low socioeconomic status show an accelerated linear growth until the 18th month of life, leading to an overcompensation of their initial height deficit. The long-term consequences of these findings remain unclear and require further study.

Associations of adult height and its components with mortality: a report from cohort studies of 135,000 Chinese women and men

BACKGROUND

Although several studies have evaluated the relationship between adult height and mortality, their results have not been entirely consistent. Little is known about components of adult height in relation to mortality, particularly in developing countries.

METHODS

We examined the association of adult height and its components (leg and trunk length) with mortality using data from 74 869 Chinese women and 61,333 men in the Shanghai Women's (1996-2008) and Men's (2002-2008) Health Studies. Anthropometric measurements, including standing and sitting height and weight, were taken at baseline by trained interviewers according to a standard protocol. Deaths were ascertained by biennial home visits and linkage with the vital statistics registry. Cox regression models were used to evaluate the associations.

RESULTS

Neither height nor its components were associated with all-cause mortality. Height and, less consistently, its components were positively associated with cancer mortality, but inversely associated with cardiovascular disease (CVD) mortality. Hazard ratios (HRs) [95% confidence intervals (CIs)] for cancer mortality per 1-SD increment in height, trunk and leg length were 1.06 (1.01-1.12), 1.07 (1.01-1.12) and 1.03 (0.98-1.08), respectively, in women, and 1.13 (1.05-1.22), 1.09 (1.00-1.19) and 1.10 (1.03-1.16), respectively, in men. The corresponding HRs for CVD mortality were 0.89 (0.84-0.95), 0.93 (0.87-0.99) and 0.91 (0.86-0.98) in women, and 0.93 (0.86-1.02), 0.89 (0.81-0.98) and 0.99 (0.92-1.06) in men.

CONCLUSIONS

Our results suggest that different mechanisms may be involved in linking height and its components with cancer and CVD mortality.

Association between socioeconomic position in earlier and later life and age at natural menopause: Estudo Pró-Saúde, Brazil

This study was based on a prospective cohort of university staff in Rio de Janeiro, Brazil (the Estudo Pró-Saúde). In this article the association between socioeconomic position (SEP) earlier and later in life and age at menopause is investigated. The main indicators investigated were for earlier SEP: mother's and father's schooling; stature; leg and trunk length. For later SEP they were: schooling; home and/or car ownership. Median age at menopause was estimated and survival curves were generated by the Kaplan-Meier method, while the association between indicators of SEP and age at menopause was explored by means of Cox semiparametric models. Associations were found between earlier SEP - represented by trunk length - and earlier menopause and between later SEP - represented by the indicator 'present schooling' - and earlier menopause. The association between earlier and later SEP was confirmed. Adverse situations over the life course can impact age at menopause and related health outcomes.

Social inequalities in height: persisting differences today depend upon height of the parents

Background

Substantial increases in height have occurred concurrently with economic development in most populations during the last century. In high-income countries, environmental exposures that can limit genetic growth potential appear to have lessened, and variation in height by socioeconomic position may have diminished. The objective of this study is to investigate inequalities in height in a cohort of children born in the early 1990s in England, and to evaluate which factors might explain any identified inequalities.

Methods and Findings

12,830 children from The Avon Longitudinal Study of Parents and Children (ALSPAC), a population based cohort from birth to about 11.5 years of age, were used in this analysis. Gender- and age-specific z-scores of height at different ages were used as outcome variables. Multilevel models were used to take into account the repeated measures of height and to analyze gender- and age-specific relative changes in height from birth to 11.5 years. Maternal education was the main exposure variable used to examine socioeconomic inequalities. The roles of parental and family characteristics in explaining any observed differences between maternal education and child height were investigated.

Children whose mothers had the highest education compared to those with none or a basic level of education, were 0.39 cm longer at birth (95% CI: 0.30 to 0.48). These differences persisted and at 11.5 years the height difference was 1.4 cm (95% CI: 1.07 to 1.74). Several other factors were related to offspring height, but few changed the relationship with maternal education. The one exception was mid-parental height, which fully accounted for the maternal educational differences in offspring height.

Conclusions

In a cohort of children born in the 1990s, mothers with higher education gave birth to taller boys and girls. Although height differences were small they persisted throughout childhood. Maternal and paternal height fully explained these differences.

Case-control study of anthropometric measures and testicular cancer risk

The etiology of testicular germ cell tumors (TGCTs) is poorly understood. Recent epidemiological findings suggest that, TGCT risk is determined very early in life, although the available data are still conflicting. The rapid growth of the testes during puberty may be another period of vulnerability. Body size has received increasing attention as possible risk factor for TC. To clarify the relation of body size and its anthropometric variables to TGCT risk, the authors analyzed data from 272 cases and 382 controls with regard to height (cm), weight (Kg), and body mass index (BMI; kg/m(2)). Overall, participants in the highest quartile of height were more likely to be diagnosed with TGCTs than participants in the lowest quartile of height, OR 2.22 (95% confidence intervals (CI): 1.25-3.93; adjusted; p(trend) = 0.033). Moreover, histological seminoma subgroup was significantly associated with tallness, very tall men (>182 cm) having a seminoma TGCT risk of OR = 2.44 (95% confidence intervals (CI): 1.19-4.97; adjusted; p(trend) = 0.011). There was also a significant inverse association of TGCT with increasing BMI (p(trend) = 0.001; age-adjusted analysis) and this association was equally present in both histological subgroups. These preliminary results indicate that testicular cancer (TC) is inversely associated with BMI and positively associated with height, in particular with seminoma subtype. Several studies have reported similar findings on body size. As adult height is largely determined by high-calorie intake in childhood and influenced by hormonal factors at puberty, increased attention to postnatal exposures in this interval may help elucidate the etiology of TGCTs.

Familial concordance for height and its components: analyses from the Breakthrough Generations Study

OBJECTIVES

To assess familial resemblance for height, arm span, and components of these, and differences between concordance for short and tall heights.

METHODS

We examined whether female relatives were similar for six anthropometric measurements (height, arm span, leg, trunk and arm length, and leg:trunk length ratio). Subjects were 31,622 related individuals aged 16-102 yr participating in the UK Breakthrough Generations Study. Height and arm span were self-reported, limb and trunk length were measured in a subset (N = 508) by study investigators, and paternal height was reported by the daughter. Data were analyzed using correlations and Poisson regression.

RESULTS

Correlation coefficients within families were 0.4 for height, 0.3 for arm span, and 0.5 for leg length, trunk length, leg:trunk ratio, and arm length. Women had a relative risk (RR) of being short (i.e., in the lowest height quintile) of 2.3 (95% confidence interval [CI] = 2.1-2.5) if their mother was short, 2.1 (95% CI = 1.9-2.3) if their father was short, and 3.7 (95% CI = 3.4-4.0) if both parents were short. RRs of being tall (i.e., in the highest height quintile) were 2.3 (95% CI = 2.1-2.5), 2.4 (95% CI = 2.2-2.6), and 4.4 (95% CI = 4.1-4.8) if their mother, father or both were tall, respectively.

CONCLUSIONS

We have shown, for the first time, that leg:trunk length ratio and arm length aggregate within families. Concordance seemed to be stronger for tall than short heights.

Physical activity, energy restriction, and the risk of pancreatic cancer: a prospective study in the Netherlands

BACKGROUND

Because of their influence on insulin concentrations, we hypothesized that both physical activity and energy restriction may reduce the risk of pancreatic cancer.

OBJECTIVE

We examined the associations between physical activity, proxies for energy restriction, and pancreatic cancer risk.

DESIGN

The Netherlands Cohort Study consisted of 120,852 individuals who completed a baseline questionnaire in 1986. After 13.3 y of follow-up, 408 cases were available for analysis. Self-reported information on physical activity was collected. Three indicators were used as proxies for energy restriction: father's employment status during the Economic Depression (1932-1940) and place of residence during the World War II years (1940-1944) and the Hunger winter (1944-1945).

RESULTS

For past sports activities, we observed a significantly decreased risk of pancreatic cancer (HR: 0.80; 95% CI: 0.64, 0.99). Proxies for energy restriction were not related to pancreatic cancer risk. When the results for energy restriction were stratified by height, a significant multiplicative interaction was observed for the Economic Depression period (P = 0.002). Shorter individuals (height less than the sex-specific median adult height) with an unemployed father during the Economic Depression period had a significantly lower cancer risk (HR: 0.31; 95% CI: 0.14, 0.66) than did taller individuals with an employed father. No significant interactions were observed for exposure to energy restriction during the World War II years and the Hunger winter.

CONCLUSIONS

Our results suggest a modestly decreased risk of pancreatic cancer associated with past sports activity. With respect to proxies for energy restriction, our findings suggest that shorter individuals exposed to energy restriction during adolescence may have a reduced risk, whereas taller individuals may not.

Body fatness during childhood and adolescence, adult height, and risk of colorectal adenoma in women

The latest report by the World Cancer Research Fund/American Institute of Cancer Research concluded that there is convincing evidence that adult height and obesity are risk factors for colorectal cancer. However, studies relating body fatness during early life to the risk of colorectal cancer or adenoma are scarce. In the Nurses' Health Study II, participants recalled adult attained height and body shape at ages 5, 10, and 20 years (using a 9-level pictogram: 1 = most lean body shape, 9 = most overweight body shape) at baseline. Among 32,707 women who had at least one lower bowel endoscopy between 1991 and 2005, 2,327 colorectal adenomas were documented. Adult height was positively associated with risk of colorectal adenoma (multivariate OR per 2 inch increment 1.05, 95% CI: 1.01-1.09). Comparing women who were overweight (body shape level 6 or higher) to women who were most lean (body shape level 1), ORs (95% CI, P(trend)) of colorectal adenoma for body shapes at ages 5, 10, and 20 years were 1.44 (1.04-1.99, 0.01), 1.21 (0.93-1.56, 0.05), and 1.03 (0.74-1.42, 0.58), respectively. Adjustment for adult body mass index did not change results substantially. The positive associations for body fatness at ages 5 and 10 years as well as adult height were restricted to distal adenoma, while not seen for proximal or rectal adenoma. Higher height and body fatness during childhood was associated with increased risk of distal adenoma later in life, independent of adult body weight.

Genetic and environmental influences on growth from late childhood to adulthood: a longitudinal study of two Finnish twin cohorts

OBJECTIVES

Human growth is a complex process that remains insufficiently understood. We aimed to analyze genetic and environmental influences on growth from late childhood to early adulthood.

METHODS

Two cohorts of monozygotic and dizygotic (same sex and opposite sex) Finnish twin pairs were studied longitudinally using self-reported height at 11-12, 14, and 17 years and adult age (FinnTwin12) and at 16, 17, and 18 years and adult age (FinnTwin16). Univariate and multivariate variance component models for twin data were used.

RESULTS

From childhood to adulthood, genetic differences explained 72-81% of the variation of height in boys and 65-86% in girls. Environmental factors common to co-twins explained 5-23% of the variation of height, with the residual variation explained by environmental factors unique to each twin individual. Common environmental factors affecting height were highly correlated between the analyzed ages (0.72-0.99 and 0.91-1.00 for boys and girls, respectively). Genetic (0.58-0.99 and 0.70-0.99, respectively) and unique environmental factors (0.32-0.78 and 0.54-0.82, respectively) affecting height at different ages were more weakly, but still substantially, correlated.

CONCLUSIONS

The genetic contribution to height is strong during adolescence. The high genetic correlations detected across the ages encourage further efforts to identify genes affecting growth. Common and unique environmental factors affecting height during adolescence are also important, and further studies are necessary to identify their nature and test whether they interact with genetic factors.

Adult stature, body proportions and age at menarche in the United States National Health and Nutrition Survey (NHANES) III

BACKGROUND

Previous studies have found that age at menarche is associated with stature, primarily via leg length. However, the effects appear to vary by population and/or time period. Improving socioeconomic conditions might amplify the association.

AIM

To test whether the association between early menarche and reduced stature in industrialized countries is mediated by leg length. To further test whether these effects are modified by years of education, as a proxy for socioeconomic conditions.

SUBJECTS AND METHODS

The study used data on from 3174 21-40 year-old women who participated in the third National Health and Nutrition Survey of the US (NHANES III). The anthropometric measurements employed were stature, sitting height and upper leg length. Leg length, lower leg length and ratio of sitting height to leg length were calculated.

RESULTS

Earlier menarche was associated with shorter stature, by ~ 3.9 mm per year of advancement, all of which was attributable to shorter leg length. Almost two-thirds of the effect was in the lower (distal) leg. Years of education did not significantly modify effects of pubertal timing on stature or body proportions.

CONCLUSION

Socioeconomic conditions might not explain variable associations between linear body proportions and pubertal timing.

Lactase persistence and milk consumption are associated with body height in Swedish preadolescents and adolescents

BACKGROUND

Body height is a classic polygenic trait. About 80%-90% of height is inherited and 10%-20% owed to environmental factors, of which the most important ones are nutrition and diseases in preadolescents and adolescents.

OBJECTIVE

The aim of this study was to explore potential relations between the LCT (lactase) C>T-13910 polymorphism, milk consumption, and body height in a sample of Swedish preadolescents and adolescents.

DESIGN

In a cross-sectional study, using a random sample of preadolescents and adolescents (n = 597), dietary intakes were determined. Anthropometric measurements including sexual maturity (Tanner stage) and birth weight were assessed. Parental body height and socio-economic status (SES) were obtained by questionnaires. Genotyping for the LCT C>T-13910 polymorphism that renders individuals lactase persistent (LP) or lactase non-persistent (LNP) was performed by DNA sequencing. Stepwise backward multivariate linear regression was used.

RESULTS

Milk consumption was significantly and positively associated with body height (β = 0.45; 95% CI: 0.040, 0.87, p = 0.032). Adjustments were performed for sex, parental height, birth weight, body mass index (BMI), SES, and Tanner stage. This model explains 90% of the observed variance of body height (adjusted R(2) = 0.89). The presence of the -13910 T allele was positively associated with body height (β = 2.05; 95% CI: 0.18, 3.92, p = 0.032).

CONCLUSIONS

Milk consumption is positively associated with body height in preadolescents and adolescents. We show for the first time that a nutrigenetic variant might be able to explain in part phenotypic variation of body height in preadolescents and adolescents. Due to the small sample size further studies are needed.

Anthropometric measures, physical activity, and risk of glioma and meningioma in a large prospective cohort study

Body fatness has been associated with increased risk of a number of hormone-dependent cancers. Recent studies suggest that body mass index (BMI) may be related to meningiomas, which are more common in women than men, and for which estrogens are believed to play a role. Using data from a large European propective cohort, 203 incident cases of meningioma and 340 cases of glioma were included in the analysis for measures of body fat, height, and physical activity among 380,775 participants. All analyses were conducted using Cox proportional hazards model and controlling for age, sex, country, and education. A 71% increase in risk of meningioma was observed among men and women in the top quartile of waist circumference (HR = 1.71, 95% CI = 1.08-2.73, P(trend) = 0.01). A positive association was also observed for BMI and meningioma (HR = 1.48, 95% CI = 0.98-2.23, for BMI ≥30 compared with a BMI of 20-24.9, P(trend) = 0.05). An association with height and meningioma was also suggestive (HR = 1.24, 95% 0.96-1.51, for each 10 cm increase). In contrast, no associations were observed for height and different measures of body fat and risk of glioma. Physical activity was not related to either type of brain tumors. Results from this study support an increase in risk of meningioma with higher body fatness among both men and women. No association was observed between anthropometric measures and risk of glioma.

Emerging options in growth hormone therapy: an update

Growth hormone (GH) was first used to treat a patient in 1958. For the next 25 years it was available only from cadaver sources, which was of concern because of safety considerations and short supply. In 1985, GH produced by recombinant DNA techniques became available, expanding its possible uses. Since that time there have been three indications approved by the US Food and Drug Administration (FDA) for GH-deficiency states and nine indications approved for non-GH-deficiency states. In 2003 the FDA approved GH for use in idiopathic short stature (ISS), which may indirectly cover other diagnoses that have short stature as a feature. However, coverage for GH therapy is usually more reliably obtainable for a specific indication, rather than the ISS indication. Possible future uses for GH therapy could include the treatment of syndromes such as Russell-Silver syndrome or chondrodystrophy. Other non-short-stature indications could include wound healing and burns. Other uses that have been poorly studied include aging and physical performance, in spite of the interest already shown by elite athletes in using GH. The safety profile of GH developed over the past 25 years has shown it to be a very safe hormone with few adverse events associated with it. The challenge for the future is to follow these patients into adulthood to determine whether GH therapy poses any long-term risks.

From Galton to GWAS: quantitative genetics of human height

Height has been studied in human genetics since the late 1800s. We review what we have learned about the genetic architecture of this trait from the resemblance between relatives and from genetic marker data. All empirical evidence points towards height being highly polygenic, with many loci contributing to variation in the population and most effect sizes appear to be small. Nevertheless, combining new genetic and genomic technologies with phenotypic measures on height on large samples facilitates new answers to old questions, including the basis of assortative mating in humans, estimation of non-additive genetic variation and partitioning between-cohort phenotypic differences into genetic and non-genetic underlying causes.

Height and cancer incidence in the Million Women Study: prospective cohort, and meta-analysis of prospective studies of height and total cancer risk

Background

Epidemiological studies have shown that taller people are at increased risk of cancer, but it is unclear if height-associated risks vary by cancer site, or by other factors such as smoking and socioeconomic status. Our aim was to investigate these associations in a large UK prospective cohort with sufficient information on incident cancer to allow direct comparison of height-associated risk across cancer sites and in relation to major potential confounding and modifying factors.

Methods

Information on height and other factors relevant for cancer was obtained in 1996–2001 for middle-aged women without previous cancer who were followed up for cancer incidence. We used Cox regression models to calculate adjusted relative risks (RRs) per 10 cm increase in measured height for total incident cancer and for 17 specific cancer sites, taking attained age as the underlying time variable. We also did a meta-analysis of published results from prospective studies of total cancer risk in relation to height.

Findings

1 297 124 women included in our analysis were followed up for a total of 11·7 million person-years (median 9·4 years per woman, IQR 8·4–10·2), during which time 97 376 incident cancers occurred. The RR for total cancer was of 1·16 (95% CI 1·14–1·17; p<0·0001) for every 10 cm increase in height. Risk increased for 15 of the 17 cancer sites we assessed, and was statistically significant for ten sites: colon (RR per 10 cm increase in height 1·25, 95% CI 1·19–1·30), rectum (1·14, 1·07–1·22), malignant melanoma (1·32, 1·24–1·40), breast (1·17, 1·15–1·19), endometrium (1·19, 1·13–1·24), ovary (1·17, 1·11–1·23), kidney (1·29, 1·19–1·41), CNS (1·20, 1·12–1·29), non-Hodgkin lymphoma (1·21, 1·14–1·29), and leukaemia (1·26, 1·15–1·38). The increase in total cancer RR per 10 cm increase in height did not vary significantly by socioeconomic status or by ten other personal characteristics we assessed, but was significantly lower in current than in never smokers (p<0·0001). In current smokers, smoking-related cancers were not as strongly related to height as were other cancers (RR per 10 cm increase in height 1·05, 95% CI 1·01–1·09, and 1·17, 1·13–1·22, respectively; p=0·0004). In a meta-analysis of our study and ten other prospective studies, height-associated RRs for total cancer showed little variation across Europe, North America, Australasia, and Asia.

Interpretation

Cancer incidence increases with increasing adult height for most cancer sites. The relation between height and total cancer RR is similar in different populations.

Funding

Cancer Research UK and the UK Medical Research Council.

Risk factors for meningioma in postmenopausal women: results from the Iowa Women's Health Study

Few risk factors for meningioma, aside from increasing age and female sex, have been identified. We investigated risk factors for meningioma in elderly women, a group with a high incidence. We evaluated associations of demographic, lifestyle, medical history, and anthropometric variables with risk of meningioma in the Iowa Women's Health Study (IWHS), a population-based, prospective cohort study. Risk factors were collected via questionnaires mailed in 1986 and 1992. Incident meningiomas were identified via linkages to Medicare. Cox regression models were used to examine the association of risk factors with meningioma incidence. The mean age at baseline of the 27,791 women in the analysis cohort was 69.3 years (range, 65.0-84.6 years). During 291,021 person-years of follow-up, 125 incident meningiomas were identified. After adjusting for age, lower levels of physical activity (relative risk [RR] , 0.68 for high versus low; P for trend = .039), greater body mass index (BMI; RR, 2.14 for ≥35 versus 19.5-24.9 kg/m(2); P for trend = .0019), greater height (RR, 2.04 for >66 versus ≤62 inches; P for trend = .013), and a history of uterine fibroids (RR, 1.72; 95% confidence interval, 1.19, 2.50) were positively associated with meningioma risk in multivariate analysis. BMI at age 18 and 30 years were not associated with risk. There were no associations with menstrual or reproductive factors or other medical history and lifestyle factors. Physical activity, BMI, height, and history of uterine fibroids were associated with meningioma risk in older women. The positive association with height suggests a role for early life influences on risk, whereas the associations with BMI and physical activity suggest a role for modifiable factors later in life.

Targeting insulin-like growth factor axis in hepatocellular carcinoma

The insulin-like growth factor (IGF) axis contains ligands, receptors, substrates, and ligand binding proteins. The essential role of IGF axis in hepatocellular carcinoma (HCC) has been illustrated in HCC cell lines and in animal xenograft models. Preclinical evidence provides ample indication that all four components of IGF axis are crucial in the carcinogenic and metastatic potential of HCC. Several strategies targeting this system including monoclonal antibodies against the IGF 1 receptor (IGF-1R) and small molecule inhibitors of the tyrosine kinase function of IGF-1R are under active investigation. This review describes the most up-to-date understanding of this complex axis in HCC, and provides relevant information on clinical trials targeting the IGF axis in HCC with a focus on anti-IGF-1R approach. IGF axis is increasingly recognized as one of the most relevant pathways in HCC and agents targeting this axis can potentially play an important role in the treatment of HCC.

Targeting insulin-like growth factor axis in hepatocellular carcinoma

The insulin-like growth factor (IGF) axis contains ligands, receptors, substrates, and ligand binding proteins. The essential role of IGF axis in hepatocellular carcinoma (HCC) has been illustrated in HCC cell lines and in animal xenograft models. Preclinical evidence provides ample indication that all four components of IGF axis are crucial in the carcinogenic and metastatic potential of HCC. Several strategies targeting this system including monoclonal antibodies against the IGF 1 receptor (IGF-1R) and small molecule inhibitors of the tyrosine kinase function of IGF-1R are under active investigation. This review describes the most up-to-date understanding of this complex axis in HCC, and provides relevant information on clinical trials targeting the IGF axis in HCC with a focus on anti-IGF-1R approach. IGF axis is increasingly recognized as one of the most relevant pathways in HCC and agents targeting this axis can potentially play an important role in the treatment of HCC.

A Review of Lifetime Risk Factors for Mortality

This review was undertaken for the Faculty and Institute of Actuaries as part of their programme to encourage research collaborations between health researchers and actuaries in order to understand better the factors influencing mortality and longevity. The authors presented their findings in a number of linked sessions at the Edinburgh conference (Joining Forces on Mortality and Longevity) in October 2009 and contributed to this overview. The purpose is to review evidence for the impact on adult mortality of characteristics of the individual's lifetime socioeconomic or psychosocial environment or phenotype at the behavioural; multi-system (e.g. cognitive and physical function); or body system level (e.g. vascular and metabolic traits) that may be common risk factors for a number of major causes of death. This review shows there is growing evidence from large studies and systematic reviews that these individual characteristics, measured in pre-adult as well as the adult life, are associated with later mortality risk. The relative contribution of lifetime environment, genetic factors and chance, whether these contributions change with age, and the underlying social and biological pathways are still to be clarified. This review identifies areas where further life course research is warranted.

Socioeconomic inequalities in height, leg length and trunk length among children aged 6.5 years and their parents from the Republic of Belarus: evidence from the Promotion of Breastfeeding Intervention Trial (PROBIT)

BACKGROUND

Lower socioeconomic position is associated with shorter stature, in particular shorter leg length, but the magnitude of these associations in non-Western countries has received little attention.

AIM

To examine socioeconomic differentials in height, leg and trunk length in 6.5 year olds from the Republic of Belarus and compare these to differentials in parental height.

METHODS

Multivariable linear regression was used to examine associations in a cohort of 13 889 children.

RESULTS

Children from non-manual households were 1.0 cm (95% confidence interval: 0.7-1.3 cm) taller than those from manual households. Mothers and fathers from non-manual backgrounds were 0.7 cm (0.5-0.8) and 1.8 cm (1.6-2.0) taller than those from manual backgrounds, respectively. Associations with higher parental educational attainment were similar. The magnitudes of the associations of socioeconomic position with leg length were similar to those with trunk length. Adjusting for mid-parental height and number of older siblings attenuated associations markedly.

CONCLUSIONS

In Belarus, similar socioeconomic differentials in height were observed in both children and their parents. Among children, height differentials were partly explained by mid-parental height and number of older siblings. Leg length was not a more sensitive indicator of childhood socioeconomic conditions than trunk length.

Height of nations: a socioeconomic analysis of cohort differences and patterns among women in 54 low- to middle-income countries

Background

Adult height is a useful biological measure of long term population health and well being. We examined the cohort differences and socioeconomic patterning in adult height in low- to middle-income countries.

Methods/Findings

We analyzed cross-sectional, representative samples of 364538 women aged 25-49 years drawn from 54 Demographic and Health Surveys (DHS) conducted between 1994 and 2008. Linear multilevel regression models included year of birth, household wealth, education, and area of residence, and accounted for clustering by primary sampling units and countries. Attained height was measured using an adjustable measuring board. A yearly change in birth cohorts starting with those born in 1945 was associated with a 0.0138 cm (95% CI 0.0107, 0.0169) increase in height. Increases in heights in more recent birth year cohorts were largely concentrated in women from the richer wealth quintiles. 35 of the 54 countries experienced a decline (14) or stagnation (21) in height. The decline in heights was largely concentrated among the poorest wealth quintiles. There was a strong positive association between height and household wealth; those in two richest quintiles of household wealth were 1.988 cm (95% CI 1.886, 2.090) and 1.018 cm (95% CI 0.916, 1.120) taller, compared to those in the poorest wealth quintile. The strength of the association between wealth and height was positive (0.05 to 1.16) in 96% (52/54) countries.

Conclusions

Socioeconomic inequalities in height remain persistent. Height has stagnated or declined over the last decades in low- to middle-income countries, particularly in Africa, suggesting worsening nutritional and environmental circumstances during childhood.

Self-reported and measured anthropometric data and risk of colorectal cancer in the EPIC-Norfolk study

BACKGROUND

Epidemiological studies have shown inconsistent results for the association between body size and colorectal cancer (CRC) risk. Inconsistencies may be because of the reliance on self-reported measures of body size.

OBJECTIVE

We examined the association of self-reported and directly assessed anthropometric data (body height, weight, body mass index (BMI), waist, hip, waist-to-hip ratio (WHR) and chest circumference) with CRC risk in the EPIC-Norfolk study.

DESIGN

A total of 20,608 participants with complete self-reported and measured height and weight and without any history of cancer were followed up an average of 11 years, during which 357 incident CRC cases were recorded. Hazard Ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models.

RESULTS

After adjustment for confounders, HRs among women in the highest quintile of the body size measure relative to the lowest quintile showed that measured height (HR=1.98, 95% CI=1.19-3.28, P (trend)=0.009), measured waist circumference (HR=1.65, 95% CI=0.97-2.86, P (trend)=0.009) and measured WHR (HR=2.07, 95% CI=1.17-3.67, P (trend)=0.001) were associated with increased CRC risk. Associations using corresponding self-reported measures were attenuated and not statistically significant. Conversely, the association of BMI with CRC risk in women was weaker using measured BMI (HR=1.57, 95% CI=0.91-2.73, P (trend)=0.05) compared with self-reported BMI (HR=1.97, 95% CI=1.18-3.30, P (trend)=0.02). In men no significantly increased CRC risk was observed with any of the anthropometric measures.

CONCLUSIONS

Measured height, waist circumference and WHR were associated with CRC risk in women, whereas any significant associations with those measures were attenuated when self-reported data were used.

Role of the growth hormone-IGF-1 axis in cancer

A substantial body of evidence supports a role for the growth hormone (GH)-IGF-1 axis in cancer incidence and progression. This includes epidemiological evidence relating elevated plasma IGF-1 to cancer incidence as well as a lack of cancers in GH/IGF-1 deficiency. Rodent models lacking GH or its receptor are strikingly resistant to the induction of a wide range of cancers, and treatment with the GH antagonist pegvisomant slows tumor progression. While GH receptor expression is elevated in many cancers, autocrine GH is present in several types, and overexpression of autocrine GH can induce cell transformation. While the mechanism of autocrine action is not clear, it does involve both STAT5 and STAT3 activation, and probably nuclear translocation of the GH receptor. Development of a more potent GH receptor antagonist or secretion inhibitor is warranted for cancer therapy.

The contribution of risk factors to the higher incidence of invasive and in situ breast cancers in women with higher levels of education in the European prospective investigation into cancer and nutrition

The authors investigated the role of known risk factors in educational differences in breast cancer incidence. Analyses were based on the European Prospective Investigation Into Cancer and Nutrition and included 242,095 women, 433 cases of in situ breast cancer, and 4,469 cases of invasive breast cancer. Reproductive history (age at first full-term pregnancy and parity), exposure to endogenous and exogenous hormones, height, and health behaviors were accounted for in the analyses. Relative indices of inequality (RII) for education were estimated using Cox regression models. A higher risk of invasive breast cancer was found among women with higher levels of education (RII = 1.22, 95% confidence interval (CI): 1.09, 1.37). This association was not observed among nulliparous women (RII = 1.13, 95% CI: 0.84, 1.52). Inequalities in breast cancer incidence decreased substantially after adjusting for reproductive history (RII = 1.11, 95% CI: 0.98, 1.25), with most of the association being explained by age at first full-term pregnancy. Each other risk factor explained a small additional part of the inequalities in breast cancer incidence. Height accounted for most of the remaining differences in incidence. After adjusting for all known risk factors, the authors found no association between education level and risk of invasive breast cancer. Inequalities in incidence were more pronounced for in situ breast cancer, and those inequalities remained after adjustment for all known risk factors (RII = 1.61, 95% CI: 1.07, 2.41), especially among nulliparous women.

Pooled analysis of two case-control studies in New Caledonia and French Polynesia of body mass index and differentiated thyroid cancer: the importance of body surface area

BACKGROUND

New Caledonia and French Polynesia have among of the world highest thyroid cancer incidence rates. Studies have demonstrated a relationship between anthropometric parameters and the prevalence of cancer. In this study we evaluated further the relationship between body mass index (BMI) and other anthropometric parameters on the incidence of thyroid cancer in the New Caledonia and French Polynesia populations.

METHODS

We performed a pooled analysis of two case-control studies in New Caledonia and French Polynesia. We included a total of 554 cases (65 men and 489 women) of differentiated thyroid cancers and 776 population control subjects matched on sex, age, and study. Anthropometric factors (height, weight, BMI, body fat percentage [BF%], and body surface area [BSA]), at age 18 and before diagnosis, were analyzed by conditional logistic regression, adjusting for other independent risk factors.

RESULTS

A high proportion of cases (73%) were overweight (25-29.9 kg/m(2)) or obese (≥30 kg/m(2)) before diagnosis of thyroid cancer (against 57% of control subjects). An increased risk of thyroid cancer was observed with greater height, weight, BMI, BF%, and BSA. The association of thyroid cancer risk with height, weight, BMI, and BF% did not remain when adjustment was made for BSA. By comparison, the odds ratios for the highest versus the lowest quartile of BSA at age 18 were 3.97 (95% confidence interval, 2.57-6.15; p < 0.001) for women and 4.06 (95% confidence interval, 1.03-16.06; p = 0.04) for men. The association between thyroid cancer risk and each of anthropometric factors did not depend on tumor size or menopausal status before diagnosis.

CONCLUSION

Among anthropometric factors, BSA plays a dominant role in thyroid cancer risk and explains the apparent role of BMI.

Maternal depressive symptoms not associated with reduced height in young children in a US prospective cohort study

BACKGROUND

Shorter stature is associated with greater all cause and heart disease mortality, but taller stature with increased risk of cancer mortality. Though childhood environment is important in determining height, limited data address how maternal depression affects linear growth in children. We examined the relationships between antenatal and postpartum depressive symptoms and child height and linear growth from birth to age 3 years in a U.S. sample.

METHODS

Subjects were 872 mother-child pairs in Project Viva, a prospective pre-birth cohort study. The study population is relatively advantaged with high levels of income and education and low risk of food insecurity. We assessed maternal depression at mid-pregnancy (mean 28 weeks' gestation) and 6 months postpartum with the Edinburgh Postnatal Depression Scale (score > = 13 on 0-30 scale indicating probable depression). Child outcomes at age 3 were height-for-age z-score (HAZ) and leg length. HAZ was also available at birth and ages 6 months, 1, 2, and 3 years.

FINDINGS

Seventy (8.0%) women experienced antenatal depression and 64 (7.3%) experienced postpartum depression. The mean (SD) height for children age 3 was 97.2 cm (4.2), with leg length of 41.6 cm (2.6). In multivariable linear regression models, exposure to postpartum depression was associated with greater HAZ (0.37 [95% confidence interval: 0.16, 0.58]) and longer leg length (0.88 cm [0.35, 1.41]). The relationship between postpartum depression and greater HAZ was evident starting at 6 months and continued to age 3. We found minimal relationships between antenatal depression and child height outcomes.

CONCLUSION

Our findings do not support the hypothesis that maternal depression is associated with reduced height in children in this relatively advantaged sample in a high-income country.

Selection for a dominant oncogene and large male size as a risk factor for melanoma in the Xiphophorus animal model

Adult height is a risk factor in numerous human cancers that involve aberrant receptor tyrosine kinase (RTK) signalling. However, its importance is debated due to conflicting epidemiological studies and the lack of useful in vivo models. In Xiphophorus fishes (Platyfishes/Swordtails), a functional RTK, Xiphophorus melanoma receptor kinase (Xmrk), serves as the dominant oncogene and has been maintained for several million years despite being deleterious and in an extremely unstable genomic region. Here we show that the Xmrk genotype is positively correlated with standard length in male and female wild caught Xiphophorus cortezi sampled throughout their phylogeographic distribution. Histopathology confirms the occurrence of malignant melanomas in both sexes; however, melanoma incidence was extremely male biased. Furthermore, males collected with malignant melanomas in the field were significantly larger than both Xmrk males collected without melanomas and wildtype (Xmrk deficient) males. These results not only provide a novel selective mechanism for the persistence of the germline Xmrk oncogene but also create an innovative avenue of melanoma research within the Xiphophorus fishes. Wildlife cancer in natural systems is a growing concern, therefore, future research investigating life history characteristics associated with certain phenotypes and genotypes that predispose an individual to cancer will be fundamental to increasing our understanding of the evolutionary biology of cancer in nature as well as in humans.

Dairy and milk consumption and child growth: Is BMI involved? An analysis of NHANES 1999-2004

Humans are unique among mammals in that many consume cow's milk or other dairy products well beyond the traditional age of weaning. Milk provides various nutrients and bioactive molecules to support growth and development, and the question arises as to whether this dietary behavior influences growth parameters. There is evidence that milk makes positive contributions to growth in height, but its associations with other aspects of body size, such as body mass index (BMI), are not well-established. National Health and Nutrition Examination Survey (NHANES) data from 1999 to 2004 and multivariate regression analysis were used to test the hypothesis that milk (g) or total dairy product consumption (kJ) is associated with higher BMI percentile among US White, Black, and Mexican-American children of age 2-4 years (n = 1,493) and 5-10 years (n = 2,526). Younger children in the highest quartile of dairy intake had higher BMIs (beta = 7.5-8.0; P < 0.01) than those in the lowest two quartiles. Controlling for energy intake eliminated differences between QIV and QI. Among children of 5-10 years of age dairy intake had no relationship to BMI. Young children in the highest quartile of milk intake had higher BMIs than all lower quartiles (beta = 7.1-12.8; beta = 6.3-11.8 in energy-controlled models; P < 0.05). Among children of 5-10 years of age, those in QIV for milk intake had higher BMIs than those in QII (beta = 8.3; beta = 7.1 in energy-controlled model; P < 0.01). Controlling for total protein or calcium did not change the results. Milk had more consistent positive associations with BMI than did dairy products, and these were strongest among children of 2-4 years of age.

The growth hormone receptor: mechanism of activation and clinical implications

Growth hormone is widely used clinically to promote growth and anabolism and for other purposes. Its actions are mediated via the growth hormone receptor, both directly by tyrosine kinase activation and indirectly by induction of insulin-like growth factor 1 (IGF-1). Insensitivity to growth hormone (Laron syndrome) can result from mutations in the growth hormone receptor and can be treated with IGF-1. This treatment is, however, not fully effective owing to the loss of the direct actions of growth hormone and altered availability of exogenous IGF-1. Excessive activation of the growth hormone receptor by circulating growth hormone results in gigantism and acromegaly, whereas cell transformation and cancer can occur in response to autocrine activation of the receptor. Advances in understanding the mechanism of receptor activation have led to a model in which the growth hormone receptor exists as a constitutive dimer. Binding of the hormone realigns the subunits by rotation and closer apposition, resulting in juxtaposition of the catalytic domains of the associated tyrosine-protein kinase JAK2 below the cell membrane. This change results in activation of JAK2 by transphosphorylation, then phosphorylation of receptor tyrosines in the cytoplasmic domain, which enables binding of adaptor proteins, as well as direct phosphorylation of target proteins. This model is discussed in the light of salient information from closely related class 1 cytokine receptors, such as the erythropoietin, prolactin and thrombopoietin receptors.

Secular changes and predictors of adult height for 86 105 male and female members of the Thai Cohort Study born between 1940 and 1990

Background

Height trends can be useful indicators of population health but, despite Thailand's rapid socioeconomic development since the 1950s, few studies have examined accompanying secular changes in adult height or the effects of the transition on the heights of rural versus urban populations. This study therefore sought to document average heights in different age groups of rural and urban Thais and to investigate factors associated with attained height.

Methods

Data from 86 105 Thai Cohort Study participants was used to estimate mean heights for men and women in different birth year groups. Simple regression was used to calculate the change in height per decade of birth year among those based in rural or urban locations as children. Multiple linear regression was used to investigate effects of other childhood factors on height.

Results

Overall, average heights were found to have increased by approximately 1 cm per decade in those born between 1940 and 1990. However, the rate of increase was 0.4–0.5 cm per decade greater among urban-based Thais compared with those from the countryside. Parental education levels, household assets, birth size, sibling number, birth rank and region of residence were also significantly associated with adult height.

Conclusions

These data suggest a marked secular increase in Thai heights in the second half of the 20th century probably reflecting improved childhood health and nutrition over this time. Rural-born Thais, who benefited to a lesser extent from the changes, may face future health challenges with greater risks of, among other things, obesity and its health consequences.

Do different measures of early life socioeconomic circumstances predict adult mortality? Evidence from the British Whitehall II and French GAZEL studies

BACKGROUND

Father's occupational position, education and height have all been used to examine the effects of adverse early life socioeconomic circumstances on health, but it remains unknown whether they predict mortality equally well.

METHODS

We used pooled data on 18,393 men and 7060 women from the Whitehall II and GAZEL cohorts to examine associations between early life socioeconomic circumstances and all-cause and cause-specific mortality.

RESULTS

During the 20-y follow-up period, 1487 participants died. Education had a monotonic association with all mortality outcomes; the age, sex and cohort-adjusted HR for the lowest versus the highest educational group was 1.45 (95% CI 1.24 to 1.69) for all-cause mortality. There was evidence of a U-shaped association between height and all-cause, cancer and cardiovascular mortality robust to adjustment for the other indicators (HR 1.41, 95% CI 1.03 to 1.93 for those shorter than average and HR 1.36, 95% CI 0.98 to 1.88 for those taller than average for cardiovascular mortality). Greater all-cause and cancer mortality was observed in participants whose father's occupational position was manual rather than non-manual (HR 1.11, 95% CI 1.00 to 1.23 for all-cause mortality), but the risks were attenuated after adjusting for education and height.

CONCLUSIONS

The association between early life socioeconomic circumstances and mortality depends on the socioeconomic indicator used and the cause of death examined. Height is not a straightforward measure of early life socioeconomic circumstances as taller people do not have a health advantage for all mortality outcomes.

Associations between anthropometry, cigarette smoking, alcohol consumption, and non-Hodgkin lymphoma in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

Prospective studies of lifestyle and non-Hodgkin lymphoma (NHL) are conflicting, and some are inconsistent with case-control studies. The Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial was used to evaluate risk of NHL and its subtypes in association with anthropometric factors, smoking, and alcohol consumption in a prospective cohort study. Lifestyle was assessed via questionnaire among 142,982 male and female participants aged 55-74 years enrolled in the PLCO Trial during 1993-2001. Hazard ratios and 95% confidence intervals were calculated using Cox proportional hazards regression. During 1,201,074 person-years of follow-up through 2006, 1,264 histologically confirmed NHL cases were identified. Higher body mass index (BMI; weight (kg)/height (m)(2)) at ages 20 and 50 years and at baseline was associated with increased NHL risk (P(trend) < 0.01 for all; e.g., for baseline BMI > or =30 vs. 18.5-24.9, hazard ratio = 1.32, 95% confidence interval: 1.13, 1.54). Smoking was not associated with NHL overall but was inversely associated with follicular lymphoma (ever smoking vs. never: hazard ratio = 0.62, 95% confidence interval: 0.45, 0.85). Alcohol consumption was unrelated to NHL (drinks/week: P(trend) = 0.187). These data support previous studies suggesting that BMI is positively associated with NHL, show an inverse association between smoking and follicular lymphoma (perhaps due to residual confounding), and do not support a causal association between alcohol and NHL.

The role of height-associated loci identified in genome wide association studies in the determination of pediatric stature

BACKGROUND

Human height is considered highly heritable and correlated with certain disorders, such as type 2 diabetes and cancer. Despite environmental influences, genetic factors are known to play an important role in stature determination. A number of genetic determinants of adult height have already been established through genome wide association studies.

METHODS

To examine 51 single nucleotide polymorphisms (SNPs) corresponding to the 46 previously reported genomic loci for height in 8,184 European American children with height measurements. We leveraged genotyping data from our ongoing GWA study of height variation in children in order to query the 51 SNPs in this pediatric cohort.

RESULTS

Sixteen of these SNPs yielded at least nominally significant association to height, representing fifteen different loci including EFEMP1-PNPT1, GPR126, C6orf173, SPAG17, Histone class 1, HLA class III and GDF5-UQCC. Other loci revealed no evidence for association, including HMGA1 and HMGA2. For the 16 associated variants, the genotype score explained 1.64% of the total variation for height z-score.

CONCLUSION

Among 46 loci that have been reported to associate with adult height to date, at least 15 also contribute to the determination of height in childhood.

Genetic dissection of intermediate phenotypes as a way to discover novel cancer susceptibility alleles

The availability of affordable genome-wide association (GWA) studies has led to the discovery of a large number of cancer risk alleles. The prospects of identifying additional alleles using the same disease-based approach are limited unless very large samples sizes are used in future investigations. An alternative and powerful way to identify additional cancer genes is to study intermediate phenotypes, such as variation in DNA repair capacity, that are known to be associated with increased disease risk. Most of these phenotypes are highly genetic. Their measurement can be achieved using well-established medium-throughput to high-throughput methods and their genetic mapping can be carried out with relatively small sample sizes. The genetic variants associated with these phenotypes will represent ideal functionally validated candidates for cancer susceptibility studies. Unlike hypothesis-free and disease-based GWA-discovered alleles, intermediate phenotype alleles that mediate cancer risk will have a strong biological relevance and will represent excellent modifiable or 'drugable' therapeutic targets.

Genome-wide association study of height and body mass index in Australian twin families

Human height and body mass index are influenced by a large number of genes, each with small effects, along with environment. To identify common genetic variants associated with these traits, we performed genome-wide association studies in 11,536 individuals composed of Australian twins, family members, and unrelated individuals at approximately 550,000 genotyped SNPs. We identified a single genome-wide significant variant for height (P value=1.06x10(-9)) located in HHIP, a well-replicated height-associated gene. Suggestive levels of association were found for other known genes associated with height (P values<1x10(-6)): ADAMTSL3, EFEMP1, GPR126, and HMGA2; and BMI (P values<1x10(-4)): FTO and MC4R. Together, these variants explain less than 2% of total phenotypic variation for height and 0.5% for BMI.

Birth length and weight as predictors of breast cancer prognosis

BACKGROUND

Birth size, and particularly birth length, is positively associated with breast cancer risk in adulthood. The objective of this study was to examine whether birth size is associated with survival among breast cancer patients.

METHODS

Information on birth size (weight, length and ponderal index (kg/length (m3)) was collected from birth archives for 331 breast cancer patients who were diagnosed at two university hospitals in Norway (Bergen and Trondheim). The patients were followed from the time of diagnosis until death from breast cancer, death from another cause, or to the end of follow-up, and birth size was related to survival, using Cox regression analysis.

RESULTS

Breast cancer patients with birth length > or = 52 cm had nearly twice the risk of dying (hazard ratio, 1.92, 95% confidence interval, 1.09-3.41) from breast cancer compared to women with birth length less than 48 cm, after adjustment for place of birth and year of diagnosis.Similar analyses related to birth weight and ponderal index showed no clear association with breast cancer survival.

CONCLUSIONS

Poorer outcome of breast cancer patients with high birth length may reflect effects of factors that stimulate longitudinal growth and simultaneously increase the risk of metastases and fatal outcome. It is possible that the insulin-like growth factor (IGF) system is involved in the underlying mechanisms.

Developmental and oncogenic effects of insulin-like growth factor-I in Ptc1+/- mouse cerebellum

Background

Medulloblastoma is amongst the most common malignant brain tumors in childhood, arising from neoplastic transformation of granule neuron precursors (GNPs) of the cerebellum via deregulation of pathways involved in cerebellar development. Deregulation of the Sonic hedgehog/Patched1 (Shh/Ptc1) signaling pathway predisposes humans and mice to medulloblastoma. In the brain, insulin-like growth factor (IGF-I) plays a critical role during development as a neurotrophic and neuroprotective factor, and in tumorigenesis, as IGF-I receptor is often activated in medulloblastomas.

Results

To investigate the mechanisms of genetic interactions between Shh and IGF signaling in the cerebellum, we crossed nestin/IGF-I transgenic (IGF-I Tg) mice, in which transgene expression occurs in neuron precursors, with Ptc1^+/- knockout mice, a model of medulloblastoma in which cancer develops in a multistage process. The IGF-I transgene produced a marked brain overgrowth, and significantly accelerated tumor development, increasing the frequency of pre-neoplastic lesions as well as full medulloblastomas in Ptc1^+/-/IGF-I Tg mice. Mechanistically, tumor promotion by IGF-I mainly affected preneoplastic stages through de novo formation of lesions, while not influencing progression rate to full tumors. We also identified a marked increase in survival and proliferation, and a strong suppression of differentiation in neural precursors.

Conclusions

As a whole, our findings indicate that IGF-I overexpression in neural precursors leads to brain overgrowth and fosters external granular layer (EGL) proliferative lesions through a mechanism favoring proliferation over terminal differentiation, acting as a landscape for tumor growth. Understanding the molecular events responsible for cerebellum development and their alterations in tumorigenesis is critical for the identification of potential therapeutic targets.

Leg length, body proportion, and health: a review with a note on beauty

Decomposing stature into its major components is proving to be a useful strategy to assess the antecedents of disease, morbidity and death in adulthood. Human leg length (femur + tibia), sitting height (trunk length + head length) and their proportions, for example, (leg length/stature), or the sitting height ratio (sitting height/stature x 100), among others) are associated with epidemiological risk for overweight (fatness), coronary heart disease, diabetes, liver dysfunction and certain cancers. There is also wide support for the use of relative leg length as an indicator of the quality of the environment for growth during infancy, childhood and the juvenile years of development. Human beings follow a cephalo-caudal gradient of growth, the pattern of growth common to all mammals. A special feature of the human pattern is that between birth and puberty the legs grow relatively faster than other post-cranial body segments. For groups of children and youth, short stature due to relatively short legs (i.e., a high sitting height ratio) is generally a marker of an adverse environment. The development of human body proportions is the product of environmental x genomic interactions, although few if any specific genes are known. The HOXd and the short stature homeobox-containing gene (SHOX) are genomic regions that may be relevant to human body proportions. For example, one of the SHOX related disorders is Turner syndrome. However, research with non-pathological populations indicates that the environment is a more powerful force influencing leg length and body proportions than genes. Leg length and proportion are important in the perception of human beauty, which is often considered a sign of health and fertility.

Parity-induced decrease in systemic growth hormone alters mammary gland signaling: a potential role in pregnancy protection from breast cancer

Early full-term pregnancy is an effective natural protection against breast cancer in both humans and experimental rodents. The protective effect of an early pregnancy is, in part, linked to changes in circulating hormones that are involved in both normal breast development and breast cancer. For example, a reduction in circulating growth hormone (GH) has been shown to protect rats from carcinogen-induced mammary tumors. We examined the ability of a full-term pregnancy to alter the endocrine GH/insulin-like growth factor-I (IGF-I) axis and how this change affected normal mammary gland function in two commonly used rat models (Sprague-Dawley and Wistar Furth). Circulating GH and IGF-I were measured in blood drawn every 30 minutes from parous and age-matched virgin female rats. Mean serum GH levels were significantly decreased (P < 0.01) in parous compared with age-matched virgin rats for both strains. Changes in GH levels were independent of estrous cycle, indicated by a significant (P < 0.05) reduction in circulating levels of GH during estrus and diestrus in both parous strains. Despite the decrease in circulating GH, pituitary GH mRNA levels were unaltered in parous rats. Circulating IGF-I and hepatic IGF-I mRNA were also unaltered by parity in either rat strain. Immunoblot analysis of mammary glands showed decreases in phosphorylation of signal transducer and activator of transcription 5A and Janus-activated kinase 2, suggesting reduced action of GH in the mammary gland. Therefore, although the parity reduction in circulating GH does not affect circulating IGF-I levels, it is possible that reduced GH acts directly at the mammary gland and may play a role in pregnancy protection from breast cancer.