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

How does socioeconomic development affect risk of mortality? An age-period-cohort analysis from a recently transitioned population in China

During the 20th century, the Hong Kong Chinese population experienced 2 abrupt but temporally distinct macroenvironmental changes: The transition from essentially preindustrial living conditions to a rapidly developing economy through mass migration in the late 1940s was followed by the emergence of an infant and childhood adiposity epidemic in the 1960s. The authors aimed to delineate the effects of these 2 aspects of economic development on mortality, thus providing a sentinel for other rapidly developing economies. Sex-specific Poisson models were used to estimate effects of age, calendar period, and birth cohort on Hong Kong adult mortality between 1976 and 2005. All-cause and cause-specific mortality, including mortality from ischemic heart disease (IHD), cardiovascular disease excluding IHD, lung cancer, other cancers, and respiratory disease, were considered. Male mortality from IHD and female mortality from other cancers increased with birth into a more economically developed environment. Cardiovascular disease mortality increased with birth after the start of the infant and childhood adiposity epidemic, particularly for men. Macroenvironmental changes associated with economic development had sex-specific effects over the life course, probably originating in early life. The full population health consequences of these changes are unlikely to manifest until persons who have spent their early lives in such environments reach an age at which they become vulnerable to chronic diseases.

Genetics of human height

Height is correlated with risk to certain diseases and various socio-economic outcomes. As an easy to observe and measure trait, it has been a classic paradigm in the emergence of fundamental concepts regarding inheritance and genetics. Resemblances in height between relatives suggest that 80% of height variation is under genetic control with the rest controlled by environmental factors such as diet and disease exposure. Nearly a century ago it was recognised that many genes were likely to be involved but it is only with recent advances in technology that it has become possible to comprehensively search the human genome for DNA variants that control height. About 50 genes and regions of the genome have been associated with height to date. These begin to explain the biological basis of height, its links to disease and aid our understanding of the evolution of human height. The genes discovered so far have a very small individual effect and hundreds, maybe thousands, more of even smaller effects are still lost in the genome. Despite a successful start to height gene mapping, there remain considerable theoretical, technological, and statistical hurdles to be overcome in order to unravel its full genetic basis.

Peptide hormone regulation of angiogenesis

It is now apparent that regulation of blood vessel growth contributes to the classical actions of hormones on development, growth, and reproduction. Endothelial cells are ideally positioned to respond to hormones, which act in concert with locally produced chemical mediators to regulate their growth, motility, function, and survival. Hormones affect angiogenesis either directly through actions on endothelial cells or indirectly by regulating proangiogenic factors like vascular endothelial growth factor. Importantly, the local microenvironment of endothelial cells can determine the outcome of hormone action on angiogenesis. Members of the growth hormone/prolactin/placental lactogen, the renin-angiotensin, and the kallikrein-kinin systems that exert stimulatory effects on angiogenesis can acquire antiangiogenic properties after undergoing proteolytic cleavage. In view of the opposing effects of hormonal fragments and precursor molecules, the regulation of the proteases responsible for specific protein cleavage represents an efficient mechanism for balancing angiogenesis. This review presents an overview of the actions on angiogenesis of the above-mentioned peptide hormonal families and addresses how specific proteolysis alters the final outcome of these actions in the context of health and disease.

HMGA2 is confirmed to be associated with human adult height

Recent genome-wide association studies have identified a novel polymorphism, rs1042725, in the HMGA2 gene for human adult height, a highly heritable complex trait. Replications in independent populations are needed to evaluate a positive finding and determine its generality. Thus, we performed a replication study to examine the associations between polymorphisms in HMGA2 and adult height in two US Caucasian populations (an unrelated sample of 998 subjects and a family-based sample of 8385 subjects) and a Chinese population (1638 unrelated Han subjects). We confirmed the association between rs1042725 in HMGA2 and adult height both in the unrelated and family-based Caucasian populations (overall P= 4.25 x 10(-9)). Another two SNPs (rs7968902 and rs7968682), which were in high linkage disequilibrium with rs1042725, also achieved the significance level in both Caucasian populations (overall P= 6.34 x 10(-7), and 2.72 x 10(-9), respectively). Our results provide strong support to the initial finding. Moreover, SNP rs1042725 was firstly found to be associated with adult height (P= 0.008) in the Chinese population, and the effect is in the same direction as in the Caucasian populations, suggesting that it is a common variant across different populations. Our study further highlights the importance of the HMGA2 gene's involvement in normal growth.

Adult height and cancer mortality in Asia: the Asia Pacific Cohort Studies Collaboration

BACKGROUND

The observation that taller people experience an increased risk of selected cancers is largely restricted to Caucasian cohorts. These associations may plausibly differ in Asian populations. For the first time, we make direct comparison in the same analyses of the associations between height and a series of malignancies in Australasian (Caucasian) and Asian populations.

METHODS

Analyses were based on the Asia Pacific Cohort Studies Collaboration of 506 648 study participants (408 381 Asia, 98 267 Australasia) drawn from 38 population-based cohort studies. Cox proportional hazards regression was used to estimate the relationship between height and cancer rates.

RESULTS

A total of 3 272 600 person-years of follow-up gave rise to 7497 cancer deaths (4415 in Asia; 3082 in Australasia). After multiple adjustments and left censoring, taller individuals experienced increased rates of carcinoma of the intestine (men and women); all cancers, liver, lung, breast, 'other' malignancies (all women); and cancers of the prostate and bladder (men). No consistent regional (Asia versus Australasia) or sex differences were observed.

CONCLUSIONS

In the present study, taller men and women had an elevated risk of selected malignancies. These associations did not differ appreciably between Asian and Caucasian populations.

Height, body mass index, and physical activity in relation to glioma risk

Whether energy balance during early life and/or adulthood is related to glioma risk is unknown. We therefore investigated height, body mass index (BMI), and physical activity in relation to glioma risk in the prospective NIH-AARP Diet and Health Study. Participants completed a baseline questionnaire (sent in 1995-1996) inquiring about height, weight, and potential confounders. A second questionnaire (sent in 1996) inquired about physical activity during ages 15 to 18, 19 to 29, and 35 to 39 years and the past 10 years and body weight at ages 18, 35, and 50 years. During follow-up from 1995/1996 to 2003, we documented 480 cases of glioma among 499,437 respondents to the baseline questionnaire and 257 cases among 305,681 respondents to the second questionnaire. Glioma risk among tall persons (>or=1.90 m) was twice that of short persons [<1.60 m; multivariate relative risk (RR), 2.12; 95% confidence interval (95% CI), 1.18-3.81; P(trend) = 0.006]. Risk among participants who were obese (BMI 30.0-34.9 kg/m(2)) at age 18 years was nearly four times that of persons of normal weight (BMI 18.5-24.9 kg/m(2)) at age 18 years (RR, 3.74; 95% CI, 2.03-6.90; P(trend) = 0.003); 11 cases were obese at age 18 years. Risk among participants who were active during ages 15 to 18 years was 36% lower than that of persons who were inactive during ages 15 to 18 years (RR, 0.64; 95% CI, 0.44-0.93; P(trend) = 0.02). BMI and physical activity after age 18 years were unrelated to glioma risk. Adult height, BMI during adolescence, and physical activity during adolescence were each associated with glioma risk, supporting a role for early-life energy balance in glioma carcinogenesis.

Breast cancer in the Thai Cohort Study: an exploratory case-control analysis

Breast cancer incidence may be increasing in Thailand but very little research has assessed core breast cancer risk factors in this country.

We used baseline questionnaire data from a national cohort study of Thai Open University students in an exploratory case-control study of breast cancer. The study included 43 female cases and 860 age-matched controls selected from the remaining 47,271 female cohort participants. Odds ratios and 95% confidence intervals were calculated using conditional logistic regression.

The women were predominantly premenopausal. Taller women had an increased risk of breast cancer (OR = 2.3, 95% CI 1.1–4.8, for height ≥160 cm vs ≤154 cm) as did women with non-insulin dependent diabetes mellitus (OR = 8.4, 95% CI 1.7–41). Women with older siblings had a reduced risk of breast cancer compared to those firstborn (OR = 0.3, 95% CI0.2–0.7).

Although limited by small case numbers, our findings suggest substantial increases in breast cancer rates in Thailand could be expected in the future.

Genetic regulation of adult stature

PURPOSE OF REVIEW

Both environmental (e.g., nutrition) and genetic factors contribute to adult height variation in the general population. However, heritability studies have shown that most of the variation in height is genetically controlled. Although height, a classic polygenic trait, has been studied for more than 100 years, the genetic factors that influence its variation remained, prior to 2007, unknown. The identification of genes that regulate human height would greatly enhance our understanding of human growth and height-associated human syndromes.

RECENT FINDINGS

Genome-wide association studies have become a powerful tool to identify genes that are associated with complex human diseases and traits. Recent large meta-analyses of genome-wide association studies for height have yielded 47 loci robustly associated with height variation. The effect of each of these height single nucleotide polymorphisms is small, yet in aggregate they can correctly assign individuals to the lower or upper tail of the height distribution. Interestingly, some of these height loci include genes that have been previously implicated by Mendelian genetics in tall or short stature syndromes, confirming the hypothesis that genes that cause syndromes can also harbor common alleles with a weaker effect on stature. Finally, the recent findings highlight biological pathways (e.g., hedgehog signaling, microRNA, chromatin structure) involved in human growth.

SUMMARY

This review summarizes the recent progress made using genome-wide association studies on the identification of common genetic variants that contribute to adult height variation in the general population.

Measuring outcomes in a longitudinal birth cohort

Longitudinal studies are often focussed on specific outcomes to address predetermined hypotheses. Nevertheless, many discoveries have been made with data collected that were not part of the original design. Measurement of a broad range of outcomes is therefore important. Here we describe examples of the types of outcome that a birth cohort should collect, with emphasis on accuracy. We emphasise the use of continuous traits as well as of dichotomous outcomes, using a variety of examples.

Height, wealth, and health: an overview with new data from three longitudinal studies

This overview, based on a literature review and new data from the three cohorts (Whitehall Studies I and II, and the Vietnam Experience Study), has four objectives: (a) to outline the major determinants of height, so providing an indication as to what exposures this characteristic may capture; (b) to summarise, by reviewing reports from large scale studies, the relation between adult height and a range of disease outcomes--both somatic and psychiatric--with particular emphasis on coronary heart disease (CHD) and stroke; (c) to discuss why these relationships may exist, in particular, the role, if any, of socioeconomic position in explaining the apparent associations; and, finally (d) to outline future research directions in this field. The large majority of evidence for predictors of height, and its health consequences, comes from observational studies. While genetic predisposition is a major determinant of height, secular rises in childhood and adult stature across successive birth cohorts suggest that early life environment also has an important impact. Plausible non-genetic determinants of height include nutrition, illness, socioeconomic status, and psychosocial stress. Evidence for an association between height and a series of health endpoints is accumulating. Thus, shorter people appear to experience increased risk of CHD, and these associations appear to be independent of socioeconomic position and other potentially confounding variables. For stroke, and its sub-types, findings are less clear. In contrast to CHD, some cancers, such as carcinoma of the colorectum, prostate, breast (in women), central nervous system, skin, endometrium, thyroid and blood (haematopoietic) are more common in taller people. While height may be negatively related to the risk of completed suicide, conclusions about the links between stature and other health endpoints is problematic given the paucity of evidence, which should be addressed. Ultimately, for want of better data, investigators in this area have used height as a proxy for a range of pre-adult exposures. In future, research should aim to explore the predictive capacity of direct measures of diet, psychosocial stress, childhood chronic illness and so on, rather than focus on height or its components. The problem is that extended follow-up of child cohorts with such data are required, and studies which hold these data are not currently available, although several are either maturing to the point where they offer sufficient clinical outcomes to facilitate analyses or are in the advanced planning stage.

Height and site-specific cancer risk: A cohort study of a korean adult population

To evaluate the association between height and risk of cancer in an East Asian, middle-income population, the authors followed up a cohort of 788,789 Koreans (449,214 men and 339,575 women) aged 40-64 years for cancer incidence between 1994 and 2003. Cox proportional hazards regression analysis was used to evaluate the association. Each 5-cm increment in height was associated with 5% and 7% higher risk of all-sites cancer in men and women, respectively, after adjustment for age, body mass index, and behavioral and socioeconomic factors. When the associations were evaluated for site-specific cancers, a positive association was observed for cancer of the colon and thyroid in both men and women. Among gender-specific cancers, prostate cancer was positively associated with height in men. In women, there was a positive association between height and cancers of the breast and ovary, which did not change even after additional adjustment for reproductive factors. Although more clarification is needed for some site-specific cancers, the same positive association of height with cancer in a middle-income Korean population as found in high-income Western populations supports the influence of early life environment on cancer development in adulthood.

Dairy consumption and female height growth: prospective cohort study

BACKGROUND

Because of its nutrients and anabolic hormones, cow's milk may promote height growth, which in turn has been related to breast cancer risk. We prospectively investigated associations between dairy intakes and height growth.

METHODS

A cohort of 5,101 girls from throughout the United States completed annual surveys (1996-2001, 2003), providing height, weight, and past-year diet. At baseline, all were premenarchal, ages 9 years and above, with no serious medical conditions. We studied three outcomes: annual height growth, peak growth velocity, and adult height. Multivariate models estimated the effects of milk, cheese, yogurt, and energy on subsequent growth, adjusted for race/ethnicity, age, prior height, and body mass index. Other models studied fats and proteins.

RESULTS

Premenarchal girls who drank >3 servings per day of milk grew 0.11 in. (P = 0.02) more the following year than girls consuming <1 serving per day. Yogurt (+0.13 in./cup; P = 0.02), but not cheese or total calories, predicted height growth. In a separate model, dairy protein (+0.034 in./10 g; P < 0.001) predicted height growth. Larger peak velocities were seen among girls reporting, at baseline, more milk (>3 glasses per day versus <1; +0.14 in., P = 0.01), more yogurt (+0.17 in./cup, P = 0.02), and, in a separate model, more dairy protein (+0.039 in./10 g; P = 0.003). Baseline milk and dairy protein predicted taller adults. Dairy protein was more important than dairy fat, for all outcomes. Nondairy animal protein and vegetable protein were never significant, nor were nondairy animal fat and vegetable fat.

CONCLUSION

Of the foods/nutrients studied, dairy protein had the strongest association with height growth. These findings suggest that a factor in the nonlipid phase of milk, but not protein itself, has growth-promoting action in girls.

A prospective Swedish study on body size, body composition, diabetes, and prostate cancer risk

Obesity may be associated with increased risk of prostate cancer (PCa). According to one hypothesis, obesity could lower the risk of non-aggressive tumours, while simultaneously increasing the risk of aggressive cancer. Furthermore, central adiposity may be independently associated with PCa risk; it is also associated with diabetes, which itself may influence risk of PCa. We studied the associations between height, body composition, and fat distribution, diabetes prevalence and risk of total, aggressive, and non-aggressive PCa in 10 564 initially cancer-free men (aged 45–73 years) of the population-based Malmö Diet and Cancer cohort. Anthropometric and body composition measurements, including bioelectrical impedance for estimation of fat mass, were performed by study nurses. Diabetes prevalence was self-reported. Cancer cases and clinical characteristics were ascertained through national and regional registry data. Dietary and other background data were obtained through a modified diet history method and an extensive questionnaire. During a mean follow-up of 11.0 years, 817 incidental PCa cases were diagnosed. Of these, 281 were classified as aggressive. There were 202 cases occurring before 65 years of age. Height was positively associated with total and non-aggressive PCa risk. Waist–hip ratio (WHR), a measure of central adiposity, was positively associated with PCa before age 65, and less strongly, with total PCa. This association was independent of body mass index (BMI) and other potential confounders. General adiposity, expressed as BMI or body fat percentage, and prevalent diabetes were not associated with PCa risk. In this study, WHR and body height were stronger PCa predictors than general adiposity.

Relationship between epidemiologic risk factors and hormone receptor expression in ovarian cancer: results from the Nurses' Health Study

Hormone receptor expression in tumors may offer etiologic information for ovarian cancer, particularly in light of known associations with hormonal and reproductive risk factors. Tissue microarrays constructed from 157 paraffin-embedded blocks of epithelial ovarian tumors collected from participants in the Nurses' Health Study were stained for estrogen receptor-alpha (ERalpha) and progesterone receptor (PR). We examined receptor expression by invasion, grade, and histologic subtype. Multivariate unconditional logistic regression was used to evaluate whether hormonal, reproductive, and anthropometric risk factors were differentially associated with the risk of developing receptor-positive or receptor-negative ovarian tumors compared with controls. PR-expressing tumors were less likely to be invasive (P = 0.05) and more likely to be of a lower grade (P < 0.001) and stage (P = 0.007) compared with PR- tumors. ERalpha status was not associated with any pathologic features of the tumor (P > 0.34). Increasing age, being postmenopausal, and postmenopausal hormone use were associated with an increased risk of developing ERalpha+, but not ERalpha- (P(heterogeneity) = 0.001, 0.06, and 0.06, respectively) and PR-, but not PR+, tumors (P(heterogeneity) = 0.08, 0.003, and 0.40, respectively), whereas height was only associated with the risk of developing PR- disease (P(heterogeneity) = 0.08). There were no clear risk differentials with OC use, parity, body mass index, or physical activity. Reproductive and hormonal risk factors are associated with subgroups of ovarian cancer defined by histologic subtype or ERalpha and PR status. These finding support specific models of hormone mediated triggers of ovarian cancer.

Growth hormone and aging: a challenging controversy

Although advanced age or symptoms of aging are not among approved indications for growth hormone (GH) therapy, recombinant human GH (rhGH) and various GH-related products are aggressively promoted as anti-aging therapies. Well-controlled studies of the effects of rhGH treatment in endocrinologically normal elderly subjects report some improvements in body composition and a number of undesirable side effects in sharp contrast to major benefits of GH therapy in patients with GH deficiency. Controversies surrounding the potential utility of GH in treatment of a geriatric patient are fueled by increasing evidence linking GH and cancer and by remarkably increased lifespan of GH-resistant and GH-deficient mice. Conservation of cellular signaling mechanisms that influence aging in organisms ranging from worms to mammals suggests that at least some of the results obtained in mutant mice are applicable to the human. We suggest that the normal, physiological functions of GH in promoting growth, sexual maturation and fecundity involve significant costs in terms of aging and life expectancy. Natural decline in GH levels during aging likely contributes to concomitant alterations in body composition and vigor but also may be offering important protection from cancer and other age-associated diseases.

Adult height and the risks of cardiovascular disease and major causes of death in the Asia-Pacific region: 21,000 deaths in 510,000 men and women

BACKGROUND

In Caucasian populations, adult height is inversely associated with cardiovascular disease (CVD) risk and positively related to some cancers. However, there are few data from Asian populations and from women. We sought to determine the sex- and region-specific associations between height and cardiovascular outcomes, and deaths due to cancer, respiratory and injury in populations from the Asia-Pacific region.

METHODS

Thirty-nine studies from the Asia Pacific Cohort Studies Collaboration database were included. We used Cox proportional hazard regression models to estimate the associations between height and pre-specified outcomes.

RESULTS

A total of 510,800 participants with 21,623 deaths were included. Amongst men, inverse linear associations were observed between height and coronary heart disease (CHD), stroke, CVD, injury and total mortality. The hazard ratios [95% confidence intervals, (CI)] for a 1-SD (= 6 cm) increment in height ranged from 0.85 (0.80-0.91) for injury to 0.97 (0.95-0.98) for total mortality. Similar trends were found between height and CHD, haemorrhagic stroke and CVD in women. A positive linear association was observed between height and cancer mortality. For each standard deviation greater height, the risk of cancer was increased by 5% (2-8%) and 9% (5-14%) in men and women, respectively. No regional difference was observed between Asian and Australasian cohorts. Adjusting for markers of education did not alter the results.

CONCLUSIONS

The opposing relationships of height with CVD and cancer suggest that care is required in setting national policies on childhood nutrition lest they have unintended consequences on the incidence of major non-communicable diseases.

Growth hormone and insulin-like growth factor-I in the transition from normal mammary development to preneoplastic mammary lesions

Adult female mammary development starts at puberty and is controlled by tightly regulated cross-talk between a group of hormones and growth factors. Although estrogen is the initial driving force and is joined by luteal phase progesterone, both of these hormones require GH-induced IGF-I in the mammary gland in order to act. The same group of hormones, when experimentally perturbed, can lead to development of hyperplastic lesions and increase the chances, or be precursors, of mammary carcinoma. For example, systemic administration of GH or IGF-I causes mammary hyperplasia, and overproduction of IGF-I in transgenic animals can cause the development of usual or atypical hyperplasias and sometimes carcinoma. Although studies have clearly demonstrated the transforming potential of both GH and IGF-I receptor in cell culture and in animals, debate remains as to whether their main role is actually instructive or permissive in progression to cancer in vivo. Genetic imprinting has been shown to occur in precursor lesions as early as atypical hyperplasia in women. Thus, the concept of progression from normal development to cancer through precursor lesions sensitive to hormones and growth factors discussed above is gaining support in humans as well as in animal models. Indeed, elevation of estrogen receptor, GH, IGF-I, and IGF-I receptor during progression suggests a role for these pathways in this process. New agents targeting the GH/IGF-I axis may provide a novel means to block formation and progression of precursor lesions to overt carcinoma. A novel somatostatin analog has recently been shown to prevent mammary development in rats via targeted IGF-I action inhibition at the mammary gland. Similarly, pegvisomant, a GH antagonist, and other IGF-I antagonists such as IGF binding proteins 1 and 5 also block mammary gland development. It is, therefore, possible that inhibition of IGF-I action, or perhaps GH, in the mammary gland may eventually play a role in breast cancer chemoprevention by preventing actions of both estrogen and progesterone, especially in women at extremely high risk for developing breast cancer such as BRCA gene 1 or 2 mutations.

Body size in early life and risk of epithelial ovarian cancer: results from the Nurses' Health Studies

Adult body mass index (BMI) has been associated with ovarian cancer risk, but few studies have examined body size earlier in life. We prospectively examined associations of body fatness at ages 5 and 10, BMI at age 18, height, and birthweight with risk of epithelial ovarian cancer in the Nurses' Health Study (NHS: 110 311 women, 735 cases) and Nurses' Health Study II (NHSII: 113 059 women, 137 cases). Cox proportional hazards regression was used to estimate relative risks (RRs) and 95% confidence intervals (CIs). There was a weak inverse association between average body fatness at ages 5 and 10 and risk in the NHS (RR for heaviest vs most lean=0.81, 95% CI: 0.53-1.24, P for trend=0.04) and a nonsignificant positive association in the NHSII (RR=2.09, 95% CI: 0.98-4.48, P for trend=0.10), possibly due to differences in age and menopausal status. Height was positively associated with risk in both cohorts (RR for >or=1.75 vs <1.6 m=1.43, 95% CI: 1.05-1.96, P for trend=0.001). Body mass index at the age of 18 years and birthweight were not associated with risk. Further research should examine the biological mechanisms underlying the observed associations.

Insulin and insulin-like growth factor signalling in neoplasia

Insulin and insulin-like growth factors (IGFs) are well known as key regulators of energy metabolism and growth. There is now considerable evidence that these hormones and the signal transduction networks they regulate have important roles in neoplasia. Epidermiological, clinical and laboratory research methods are being used to investigate novel cancer prevention and treatment strategies related to insulin and IGF signalling. Pharmacological strategies under study include the use of novel receptor-specific antibodies, receptor kinase inhibitors and AMP-activated protein kinase activators such as metformin. There is evidence that insulin and IGF signalling may also be relevant to dietary and lifestyle factors that influence cancer risk and cancer prognosis. Recent results are encouraging and have justified the expansion of many translational research programmes.

Tonsillectomy and breast cancer risk in the Western New York Diet Study

OBJECTIVES

Exposures during early life may affect risk of breast cancer. History of tonsillectomy has recently been associated with risk of several cancers, including cancer of the breast.

METHODS

We conducted a population-based case-control study of women living in Western New York from 1986 to 1991. Cases had incident, primary, pathologically confirmed breast cancer and were recruited through all major hospitals in the region (n = 740). Population-based controls (n = 810) were randomly sampled from among drivers' license holders from Department of Motor Vehicles records (<65 yrs) and from Health Care Finance Administration records (> or =65 yrs). Participants were interviewed with regard to diet, anthropometrics, demographics, medical, and reproductive history. Unconditional logistic regression models stratified by menopausal status were used to estimate multivariate odds ratios (OR) and 95% confidence intervals (95% CI).

RESULTS

A history of tonsillectomy was associated with increased breast cancer risk among premenopausal (OR 1.50, 95% CI: 1.08-2.08) but not postmenopausal women (OR 1.05, 95% CI: 0.79-1.38).

CONCLUSIONS

Our findings add to accumulating data implicating tonsillectomy in risk of cancer. Tonsillectomy may be an indicator for conditions of chronic inflammation and/or reduced efficiency of immune function. Our study also provides additional evidence that early life exposures may affect premenopausal breast cancer risk.

Reaching new heights: insights into the genetics of human stature

Human height is a highly heritable, classic polygenic trait. Until recently, there had been limited success in identifying the specific genetic variants that explain normal variation of human height. The advent of large-scale genome-wide association studies, however, has led to dramatic progress. In the past 18 months, the first robust common variant associations were identified and there are now 44 loci known to influence normal variation of height. In this review, we summarize this exciting recent progress, discuss implicated biological pathways, the overlap with monogenic growth and skeletal dysplasia syndromes, links to disease and insights into the genetic architecture of this model polygenic trait. We also discuss the strong probability of finding several hundred more such loci in the near future.

Height and prostate cancer risk: a large nested case-control study (ProtecT) and meta-analysis

BACKGROUND

Height, a marker of childhood environmental exposures, is positively associated with prostate cancer risk, perhaps through the insulin-like growth factor system. We investigated the relationship of prostate cancer with height and its components (leg and trunk length) in a nested case-control study and with height in a dose-response meta-analysis.

METHODS

We nested a case-control study within a population-based randomized controlled trial evaluating treatments for localized prostate cancer in British men ages 50 to 69 years, including 1,357 cases detected through prostate-specific antigen testing and 7,990 controls (matched on age, general practice, assessment date). Nine bibliographic databases were searched systematically for studies on the height-prostate cancer association that were pooled in a meta-analysis.

RESULTS

Based on the nested case-control, the odds ratio (OR) of prostate-specific antigen-detected prostate cancer per 10 cm increase in height was 1.06 [95% confidence interval (95% CI): 0.97-1.16; p(trend) = 0.2]. There was stronger evidence of an association of height with high-grade prostate cancer (OR: 1.23; 95% CI: 1.06-1.43), mainly due to the leg component, but not with low-grade disease (OR: 0.99; 95% CI: 0.90-1.10). In general, associations with leg or trunk length were similar. A meta-analysis of 58 studies found evidence that height is positively associated with prostate cancer (random-effects OR per 10 cm: 1.06; 95% CI: 1.03-1.09), with a stronger effect for prospective studies of more advanced/aggressive cancers (random-effects OR: 1.12; 95% CI: 1.05-1.19).

CONCLUSION

These data indicate a limited role for childhood environmental exposures-as indexed by adult height-on prostate cancer incidence, while suggesting a greater role for progression, through mechanisms requiring further investigation.

Childhood stature and adult cancer risk: the Boyd Orr cohort

Cancer risk in adulthood may be influenced by aspects of childhood diet. In the absence of direct dietary data, indirect measures of childhood diet and nutritional status, such as anthropometric measurements, may be useful in investigating diet-cancer associations. Previous studies suggest that taller adults may have increased cancer risk. Peak growth for different anthropometric measures occurs at different times and so differential associations with cancer risk may indicate periods of development that are particularly important in determining future risk. 2,642 traced members of the Boyd Orr cohort had measures of foot length, shoulder breadth, height, and leg length made when they were aged 2-14 years; trunk length was derived from the difference between overall height and leg length. Subjects were followed-up over 59 years to determine all-cause (n = 547) and site-specific (n = 97 for lung, 69 breast, 59 colorectal, 33 prostate, 320 not related to smoking) cancer deaths and registrations. There were no strong associations between childhood anthropometric measurements and adult cancer risk. Odds ratios (ORs) were broadly consistent with a slight increase in risk with increasing childhood stature but no single measure was of particular importance. The strongest associations were seen for breast cancer (OR per standard deviation increase in foot length: 1.16 (95% CI: 0.90, 1.51), shoulder breadth: 1.16 (0.91, 1.49) and trunk: 1.26 (1.00, 1.60), and prostate cancer (OR for foot length: 1.22 (0.86, 1.75)). There was little effect of adjustment for confounding factors and very limited evidence that associations differed with measures made prior to the onset of puberty (comparing the associations in children aged <8 vs. 8+ years). There was no evidence that any of the five indicators of childhood growth was more strongly related to cancer risk than the other measures.

Examining breast cancer growth and lifestyle risk factors: early life, childhood, and adolescence

The perinatal period, childhood, and adolescence are important intervals for breast cancer risk development. Endogenous estrogen exposure is thought to be highest in utero, and exposure to estrogens throughout life plays an important role in increasing breast cancer risk. Some evidence suggests that breast tissue is not fully differentiated until after the first full-term pregnancy; thus, breast tissue might be more susceptible to carcinogenic influences during early life and adolescence. Birth characteristics of the daughter, including gestational age, birth weight, and birth length are associated with maternal hormone levels during the index pregnancy, and birth size has been related to daughter's timing of puberty and adult breast cancer incidence. Furthermore, early life and adolescence are critical times for maturation of the hypothalamic pituitary ovarian axis, which regulates production of ovarian hormones including estrogen and progesterone. Childhood height, growth, diet, and body mass index (BMI) have also been associated with breast cancer risk later in life. Of the examined characteristics, we conclude that the available evidence is suggestive of a positive relationship of breast cancer risk with birth weight, birth length, and adolescent height, and an inverse relationship with gestational age and childhood BMI, although several inconsistencies exist in the literature. The best evidence for a relationship of adolescent diet and adult breast cancer risk is indirect, and the relationship of diet, weight status, and weight gain in childhood deserves further attention. The interaction of birth characteristics with established risk factors over the life course, such as age at menarche, in addition to gene-environment interactions, require more research. Further study is also needed to clarify the biologic mechanisms influencing the observed associations.

Tallness is associated with risk of testicular cancer: evidence for the nutrition hypothesis

The pathogenesis of testicular germ cell tumours (GCTs) is potentially influenced by high-energy nutrition during infancy. As adult height is a proxy for childhood nutrition, we investigated the role of nutrition in GCT pathogenesis by comparing stature of patients with healthy men. In a matched case–control study, 6415 patients with GCT were compared with healthy army conscripts (1:6 matching modus) with regard to height (cm) and body mass index (BMI; kg/m²). Statistical analysis involved tabulation of descriptive height measures and BMI. Conditional logistic regression models were used to quantify the association of GCT with height, with odds ratios (OR) adjusted for BMI. The literature was searched for studies on stature in GCT patients. Body size is significantly associated with risk of GCT, very tall men (>195 cm) having a GCT risk of OR=3.35 (95% confidence intervals (CI): 2.88–3.90; adjusted). Short stature is protective (OR=0.798; 95% CI: 0.68–0.93). Both histologic subgroups are associated with tallness. Of 16 previous reports, 7 were confirmative, 5 had null and 4 equivocal results. The association of stature with GCT risk accords with the nutrition hypothesis of GCT. This study expands the current view of GCT tumorigenesis by suggesting that high-calorie intake in childhood promotes GCT precursors originating in utero.

Lower urinary tract symptoms and risk of prostate cancer: the HUNT 2 Cohort, Norway

Screening for early prostate cancer is frequently employed in the routine management of men with lower urinary tract symptoms (LUTS), but the evidence-base linking LUTS with prostate cancer is limited. We assessed the association of LUTS with a subsequent prostate cancer diagnosis in a prospective cohort study based on 21,159 Norwegian men who completed baseline questionnaires, including the International Prostate Symptom Score (IPSS) questionnaire, between 1995 and 2007 as part of the second Nord-Trøndelag Health Study (HUNT 2). Men were followed-up for prostate cancer incidence and mortality from the date of clinical examination to end 2005. During a mean of 9 years follow-up, 518 incident prostate cancers were diagnosed and 74 men died from prostate cancer. Men with severe LUTS (IPSS 20-35) had a 2.26-fold (95% CI: 1.49-3.42) increased risk of prostate cancer compared to men reporting no symptoms. A positive association was observed for localized (hazard ratio, HR: 4.61; 2.23-9.54), but not advanced (HR: 0.51; 0.15-1.75), cancers (p for heterogeneity <0.001). There was no evidence that moderate/severe symptoms (IPSS 8-35) were associated with prostate cancer mortality (HR: 0.83; 0.42-1.64) vs. no symptoms. Amongst 518 men with prostate cancer, there was a 46% lower (10-68%) risk of death with moderate/severe symptoms vs. no symptoms. We conclude that LUTS are positively associated with localized, but not advanced or fatal, prostate cancer, suggesting that urinary symptoms are not caused by prostate cancer. Thus, screening for early cancers on the basis of LUTS may not be justified.

Association of HMGA2 Gene Variation with Height in Specific Pediatric Age Categories

Background

Recently an association was demonstrated between the single nucleotide polymorphism (SNP), rs1042725, within the HMGA2 locus and height as a consequence of a genome wide association (GWA) study of this trait in adults; this observation was also reported in children aged 7–11 years old.

Objective

We examined in our Caucasian childhood cohort the effects of two strong surrogates for this SNP at this locus with height, rs8756 and rs7968902, with respect to the same pediatric age category but also in children grouped separately as younger and older.

Methods

Utilizing data from an ongoing GWA study in our cohort of 2,619 Caucasian children with measurements for height, we investigated the association of the previously reported variation at the HMGA2 locus with this height treated as a quantitative trait (age and sex corrected) in childhood in the 2–6 (n = 706), 7–11 (n = 617) and 12–18 (n = 1293) years old categories.

Results

The minor alleles of rs8756 and rs7968902 respectively (strong surrogates for rs1042725 i.e. r 2 = 0.873 and 0.761 in the CEU HapMap respectively) were significantly associated with height in the 7–11 years old age group ( P = 3.53 × 10–3 and 2.82 × 10–4, respectively) However in the 2–6 and 12–18 years old age groups, no association was observed.

Conclusions

We observe a strong association with height in same age group of 7–11 years old as has been previously reported. However, in the under 7s and the over 11s, no such association was observed.

Adult height and the risk of mortality in South Korean women

To evaluate the association between adult height as a surrogate marker of childhood circumstances and the risk of mortality, 344,519 South Korean women aged 40-64 years categorized into six height groups were prospectively followed for mortality between 1994 and 2004. In Cox proportional hazards regression with adjustment for behavioral and biologic risk factors, there was an inverse association between height and total mortality; mortality risk decreased 7% for each 5-cm increment in height. The association did not materially change after adjustment for behavioral factors and adulthood socioeconomic factors or after full adjustment for all available covariates. When height-associated risks of death from specific causes were evaluated in a fully adjusted analysis, a 5-cm increment in height was associated with lower risks of death from respiratory diseases, stroke, diabetes mellitus, and external causes (hazard ratios were 0.84 (95% confidence interval (CI): 0.74, 0.96), 0.84 (95% CI: 0.80, 0.88), 0.87 (95% CI: 0.80, 0.96), and 0.88 (95% CI: 0.83, 0.94), respectively) and with a higher risk of death from cancer (hazard ratio = 1.05, 95% CI: 1.02, 1.09). Given that adult height reflects early-life conditions, the independent associations between height and mortality from all causes and specific causes support the view that early-life circumstances significantly influence health outcomes in adulthood.

Insulin, insulin-like growth factors and neoplasia

Over the past decade, dozens of epidemiological studies and laboratory experiments have provided evidence for relationships between insulin-like growth factor (IGF) physiology and neoplasia. Population studies provide evidence for a modestly increased risk of a subsequent cancer diagnosis in subjects with IGF-I levels at the high end of the broad normal range, as compared to those at the low end of the normal range. At the cellular level, IGF-I receptor signalling has been shown to play an important role in facilitating the transforming action of a variety of oncogenes. Reducing receptor function with anti-receptor antibodies or specific tyrosine kinase inhibitors reduces the proliferation of many cancers in vitro and in vivo. At present, clinical relevance of the relationship between circulating IGF-I level and cancer risk is limited, but in terms of experimental therapeutics, many clinical trials have been initiated to investigate the possibility that the paradigm of hormonal treatment of cancer may be extended from targeting gonadal steroids to targeting the growth hormone-IGF-I axis.

Body size and renal cell cancer incidence in a large US cohort study

Renal cell cancer (RCC) incidence has increased in the United States over the past three decades. The authors analyzed the association between body mass index (BMI) and invasive RCC in the National Institutes of Health (NIH)-AARP Diet and Health Study, a large, prospective cohort aged 50-71 years at baseline initiated in 1995-1996, with follow-up through December 2003. Detailed analyses were conducted in a subcohort responding to a second questionnaire, including BMI at younger ages (18, 35, and 50 years); weight change across three consecutive age intervals; waist, hip, and waist-to-hip ratio; and height at age 18 years. Incident RCC was diagnosed in 1,022 men and 344 women. RCC was positively and strongly related to BMI at study baseline. Among subjects analyzed in the subcohort, RCC associations were strongest for baseline BMI and BMI recalled at age 50 years and were successively attenuated for BMI recalled at ages 35 and 18 years. Weight gain in early (18-35 years of age) and mid- (35-50 years of age) adulthood was strongly associated with RCC, whereas weight gain after midlife (age 50 years to baseline) was unrelated. Waist-to hip ratio was positively associated with RCC in women and with height at age 18 years in both men and women.

Lifestyle factors and primary glioma and meningioma tumours in the Million Women Study cohort

Previous studies have reported inconsistent results on the effect of anthropometric and lifestyle factors on the risk of developing glioma or meningioma tumours. A prospective cohort of 1.3 million middle-aged women was used to examine these relationships. During 7.7 million women-years of follow-up, a total of 1563 women were diagnosed with a primary incident central nervous system tumour: 646 tumours were classified as glioma and 390 as meningioma. Our results show that height is related to the incidence of all central nervous system tumours with a risk of about 20% per 10 cm increase in height (relative risk=1.19, 95% CI=1.10–1.30 per 10 cm increase in height, P<0.001): the risks did not differ significantly between specified glioma and meningioma. Body mass index (BMI) was also related to central nervous system tumour incidence, with a risk of about 20% per 10 kg m⁻² increase in BMI (relative risk=1.17, 95% CI=1.03–1.34 per 10 kg m⁻² increase in BMI, P=0.02). Smoking status, alcohol intake, socioeconomic level, parity, age at first birth, and oral contraceptive use were not associated with the risk of glioma or meningioma tumours. In conclusion, for women in the United Kingdom, the incidence of glioma or meningioma tumours increases with increasing height and increasing BMI.

Identification of ten loci associated with height highlights new biological pathways in human growth

Height is a classic polygenic trait, reflecting the combined influence of multiple as-yet-undiscovered genetic factors. We carried out a meta-analysis of genome-wide association study data of height from 15,821 individuals at 2.2 million SNPs, and followed up the strongest findings in >10,000 subjects. Ten newly identified and two previously reported loci were strongly associated with variation in height (P values from 4 x 10(-7) to 8 x 10(-22)). Together, these 12 loci account for approximately 2% of the population variation in height. Individuals with < or =8 height-increasing alleles and > or =16 height-increasing alleles differ in height by approximately 3.5 cm. The newly identified loci, along with several additional loci with strongly suggestive associations, encompass both strong biological candidates and unexpected genes, and highlight several pathways (let-7 targets, chromatin remodeling proteins and Hedgehog signaling) as important regulators of human stature. These results expand the picture of the biological regulation of human height and of the genetic architecture of this classical complex trait.

Height, body mass index, and ovarian cancer: a pooled analysis of 12 cohort studies

BACKGROUND

Although many studies have investigated the association between anthropometry and ovarian cancer risk, results have been inconsistent.

METHODS

The associations of height, body mass index (BMI), and ovarian cancer risk were examined in a pooled analysis of primary data from 12 prospective cohort studies from North America and Europe. The study population consisted of 531,583 women among whom 2,036 epithelial ovarian cancer cases were identified. To summarize associations, study-specific relative risks (RR) were estimated using the Cox proportional hazards model and then combined using a random-effects model.

RESULTS

Women with height > or =1.70 m had a pooled multivariate RR of 1.38 [95% confidence interval (95% CI), 1.16-1.65] compared with those with height <1.60 m. For the same comparison, multivariate RRs were 1.79 (95% CI, 1.07-3.00) for premenopausal and 1.25 (95% CI, 1.04-1.49) for postmenopausal ovarian cancer (P(interaction) = 0.14). The multivariate RR for women with a BMI > or =30 kg/m(2) was 1.03 (95% CI, 0.86-1.22) compared with women with a BMI from 18.5 to 23 kg/m(2). For the same comparison, multivariate RRs were 1.72 (95% CI, 1.02-2.89) for premenopausal and 1.07 (95% CI, 0.87-1.33) for postmenopausal women (P(interaction) = 0.07). There was no statistically significant heterogeneity between studies with respect to height or BMI. BMI in early adulthood was not associated with ovarian cancer risk.

CONCLUSION

Height was associated with an increased ovarian cancer risk, especially in premenopausal women. BMI was not associated with ovarian cancer risk in postmenopausal women but was positively associated with risk in premenopausal women.

The contribution of growth hormone to mammary neoplasia

While the effects of growth hormone (GH) on longitudinal growth are well established, the observation that GH contributes to neoplastic progression is more recent. Accumulating literature implicates GH-mediated signal transduction in the development and progression of a wide range malignancies including breast cancer. Recently autocrine human GH been demonstrated to be an orthotopically expressed oncogene for the human mammary gland. This review will highlight recent evidence linking GH and mammary carcinoma and discuss GH-antagonism as a potential therapeutic approach for treatment of breast cancer.

How growth hormone may be linked to cancer: concerns and perspective

Recent evidence from epidemiology indicates that inter-individual variations in the growth hormone (GH)/IGF-I pathway affect the risk of individuals developing common epithelial cancers. This is supported by associations between normal common variants within genes from the pathway and these cancers, which excludes many potential confounding issues, such as reverse causality. This raises concern for the increasing numbers of patients treated with GH; although replacement therapy for GH-deficiency should aim to restore normality, which should then only incur a normal risk. The links with cancer also offers promising new opportunities. Clinical trials treating cancer patients with pharmaceuticals targeting the IGF-I receptor are well advanced with promising initial findings. In the future, there has to be much more emphasis within oncology on prevention and the GH/IGF-I pathway is one of few identified risk factors that are modifiable, not just by pharmaceutical, but also nutritional, interventions that may, in the long term, be more appropriate. Assessing the status of the GH/IGF-I pathway in individuals may also provide a means for targeting screening programs and preventative measures.

Early life influences on adult leg and trunk length in the 1958 British birth cohort

OBJECTIVES

Short leg length has been associated with increased disease risk. We investigated (1) whether taller childhood stature predicts longer adult leg than trunk length; (2) the effects of early life factors on adult leg/trunk length.

METHODS

We used data from the 1958 British birth cohort on height in childhood and at 45 years, leg and trunk length at 45 years and early life factors (n approximately 5,900).

RESULTS

For a SD increase in height at 7 years, adult leg length increased more than trunk length (2.5-2.8 cm vs. 1.9 cm). Parental height had a stronger association with adult than childhood height, and leg than trunk length. Prenatal factors were associated with leg (maternal smoking) and trunk length (birth order); birth weight had a similar effect on leg and trunk lengths. Large family size, overcrowding, and social housing were more strongly associated with leg than trunk length: deficits in adult height (0.4-0.8 cm) were mostly due to shorter legs.

CONCLUSIONS

Socio-economic adversity in childhood is associated with delayed early growth, shorter adult leg length, and stature. Leg length is the height component most sensitive to early environment. Studies of early life and adult disease could usefully assess adult leg length in addition to height.

Height and body mass index in young adulthood and risk of schizophrenia: a longitudinal study of 1 347 520 Swedish men

OBJECTIVE

Measures of body size reflect genetic and environmental influences on growth and energy balance. Associations between such measures and risk of schizophrenia have been inconsistent.

METHOD

This is a population-based cohort study of 1 347 520 men born in Sweden from 1952 to 1982, with height and body mass index (BMI) data available from conscription records. The Swedish National Hospital Discharge Register was used to identify subjects diagnosed with schizophrenia from 1970 to 2000.

RESULTS

Subjects with lower BMI and shorter height had an increased risk of developing schizophrenia. Underweight subjects had an approximately 30% increase in risk compared with normal BMI subjects (adjusted HR = 1.30, 95% CI: 1.20-1.42). Tall subjects had an approximately 15% reduction in risk compared with short subjects (adjusted HR = 0.85, 95% CI: 0.80-0.92).

CONCLUSION

Both height and BMI in early adulthood are strongly and inversely associated with risk of schizophrenia. We discuss these findings in relation to possible genetic and nutritional causal mechanisms.

Relative leg length as a biological marker to trace the developmental history of individuals and populations: growth delay and increased body fat

The purpose of this study was to determine whether differences in leg length index are related to differences in body fat. The study included a cross-sectional sample of 21,021 subjects ranging in age from 2 to 90 years who had anthropometric information and poverty income ratio that participated in the third National Health and Nutrition Survey (NHANES III) of the United Stated conducted during 1988-1994. Of the total 21,021 participants, 7,810 were non-Hispanic white (3,900 men and 3,910, women), 8,134 were African-American black (3,127 men and 2,889 women) and 6,237 were Mexican-American (3,221 and 3,016 women). In both males and females and in all three ethnic groups and across socio-economic status (measured by the poverty income ratio) a low leg length index is associated with increased body fat (measured by skinfold thickness) when compared with those with high leg length index. It is postulated that a low leg length index reflects the consequence of negative environmental conditions leading to growth delay. Previous studies indicate that individuals exposed both during development and adulthood to under-nutrition respond through inter-related physiological mechanisms oriented at improving energetic efficiency and low oxidation of fat. These interrelated compensatory physiological adjustments work together to promote fat storage among growth delayed individuals or populations.

A common variant of HMGA2 is associated with adult and childhood height in the general population

Human height is a classic, highly heritable quantitative trait. To begin to identify genetic variants influencing height, we examined genome-wide association data from 4,921 individuals. Common variants in the HMGA2 oncogene, exemplified by rs1042725, were associated with height (P = 4 x 10(-8)). HMGA2 is also a strong biological candidate for height, as rare, severe mutations in this gene alter body size in mice and humans, so we tested rs1042725 in additional samples. We confirmed the association in 19,064 adults from four further studies (P = 3 x 10(-11), overall P = 4 x 10(-16), including the genome-wide association data). We also observed the association in children (P = 1 x 10(-6), N = 6,827) and a tall/short case-control study (P = 4 x 10(-6), N = 3,207). We estimate that rs1042725 explains approximately 0.3% of population variation in height (approximately 0.4 cm increased adult height per C allele). There are few examples of common genetic variants reproducibly associated with human quantitativetraits; these results represent, to our knowledge, the first consistently replicated association with adult and childhood height.

Using anthropometric indicators for Mexicans in the United States and Mexico to understand the selection of migrants and the "Hispanic paradox"

Anthropometric measures including height provide an indication of childhood health that allows exploration of relationships between early life circumstances and adult health. Height can also be used to provide some indication of how early life health is related to selection of migrants and the Hispanic paradox in the United States. This article joins information on persons of Mexican nativity ages 50 and older in the United States collected in the National Health and Nutrition Examination Survey IV (NHANES IV 1999-2002) with a national sample of persons of the same age living in Mexico from the Mexican Health and Aging Survey (MHAS 2001) to examine relationships between height, education, migration, and late-life health. Mexican immigrants to the United States are selected for greater height and a high school, rather than higher or lower, education. Return migrants from the United States to Mexico are shorter than those who stay. Height is related to a number of indicators of adult health. Results support a role for selection in the Hispanic paradox and demonstrate the importance of education and childhood health as determinants of late-life health in both Mexico and the United States.