Body height, cardiovascular risk factors, and risk of stroke in middle-aged men and women. A 14-year follow-up of the Finnmark Study

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.

Hyperglycemia and stroke mortality: comparison between fasting and 2-h glucose criteria

OBJECTIVE

We investigated stroke mortality in individuals in different categories of glycemia and compared hazard ratios (HRs) corresponding to a 1-SD increase in 2-h plasma glucose and fasting plasma glucose (FPG) criteria.

RESEARCH DESIGN AND METHODS

We examined data from 2-h 75-g oral glucose tolerance tests taken from 13 European cohorts comprising 11,844 (55%) men and 9,862 (45%) women who were followed up for a median of 10.5 years. A multivariate adjusted Cox proportional hazards model was used to estimate HRs for stroke mortality.

RESULTS

In men and women without a prior history of diabetes, multivariate adjusted HRs for stroke mortality corresponding to a 1-SD increase in FPG were 1.02 (95% CI 0.83-1.25) and 1.52 (1.22-1.88) and those in 2-h plasma glucose 1.21 (1.06-1.38) and 1.31 (1.06-1.61), respectively. Addition of 2-h plasma glucose to the model with FPG significantly improved prediction of stroke mortality in men (chi2 = 10.12; P = 0.001) but not in women (chi2 = 0.01; P = 0.94), whereas addition of FPG to 2-h plasma glucose improved stroke mortality in women (chi2 = 4.08; P = 0.04) but not in men (chi2 = 3.29; P = 0.07).

CONCLUSIONS

Diabetes defined by either FPG or 2-h plasma glucose increases the risk of stroke mortality. In individuals without a history of diabetes, elevated 2-h postchallenge glucose is a better predictor than elevated fasting glucose in men, whereas the latter is better than the former in women.

Effects of an individualized multimedia computer program for health education in patients with a recent minor stroke or transient ischemic attack - a randomized controlled trial

BACKGROUND

Transient ischemic attack (TIA) and stroke patients often show a striking lack of knowledge about their disease. We developed a computer program that provided health education fitting the educational level, risk profile and symptoms of patients and evaluated it in a randomized controlled trial.

METHODS

Transient ischemic attack or minor stroke patients were allocated to health education by a physician (n = 32) or to a combination of education by a physician and the computer program (n = 33). Knowledge was tested by means of a questionnaire at 1 and 12 weeks after inclusion. The maximum possible score was 71 points.

RESULTS

Overall knowledge was low - the mean score was 43.6 at 1 week and 42.0 points at 12 weeks for both the groups. The intervention group had slightly better scores at 1 week after using the computer program, 45.4 vs 41.5 (P = 0.09), with the difference increasing to 4.3 points after (post-hoc) adjustment for age and level of education (P = 0.06). After 12 weeks, the score in the intervention group dropped significantly to 42.0 points (P = 0.05), and was no longer different from the standard group.

CONCLUSION

This study did not show a lasting effect of health education by an individualized computer program on the knowledge of TIA and minor stroke patients.

Prospective study of body size and risk for stroke amongst women below age 60

The relation between obesity, particularly abdominal obesity, and risk of stroke amongst women remains unclear. In 1991-1992, a prospective study was initiated in Sweden amongst women who returned a self-administered questionnaire. Through linkage with nation-wide registries, 45,449 women, free of stroke at entry, were followed up until diagnosis of first incident stroke, death, or the end of follow-up in 2002. We estimated multivariate relative risks (RRs) with 95% confidence intervals (CIs) from Cox proportional hazards regression models. A total of 170 incident stroke cases occurred during an average of 11 years of follow-up. The RR of stroke amongst women in the highest compared with the lowest quintile was 2.4 (95% CI 1.3-4.2; P for trend 0.04) for waist-to-hip ratio, 2.5 (95% CI 1.5-4.3; P for trend 0.01) for waist-to-height ratio and 2.3 (95% CI 1.2-4.3; P for trend 0.02) for waist circumference. Adjustment for hypertension and diabetes attenuated these risk estimates. In contrast, birth weight, body mass index (BMI) at age 18, BMI at entry, weight change in adulthood and adult height were not significantly associated with risk of stroke. This study provides evidence that, in contrast to BMI, several different measures of abdominal obesity are strong predictors of stroke in women.

Weight reduction for primary prevention of stroke in adults with overweight or obesity

BACKGROUND

Obesity is seen as a worldwide chronic disease with high prevalence that has been associated with increased morbidity from many conditions including stroke, which is the third leading cause of death in developed countries and a leading cause of severe long-term disability. The causal association between overweight or obesity and stroke is unclear and there is no definite study clarifying the role of obesity treatment in the prevention of a first stroke (primary prevention). Given the prevalence of stroke and the enormous health and economic cost of the disease, it is important to establish the possible impact of weight reduction per se on stroke incidence.

OBJECTIVES

To assess the effects of weight reduction in people with overweight or obesity on stroke incidence.

SEARCH STRATEGY

MEDLINE, EMBASE, The Cochrane Library, LILACS, databases of ongoing trials and reference lists were used to identify relevant trials. The last search was conducted in April 2006.

SELECTION CRITERIA

Randomised controlled trials comparing any intervention for weight reduction (single or combined) with placebo or no intervention in overweight or obese people.

DATA COLLECTION AND ANALYSIS

No trials were found in the literature for inclusion in this review.

MAIN RESULTS

There are currently no results to be reported.

AUTHORS' CONCLUSIONS

Obesity seems to be associated with an increased risk of stroke and it has been suggested that weight loss may lead to a reduction of stroke occurrence. However, this hypothesis is not based on strong scientific evidence resulting from randomised controlled clinical trials. This systematic review identified the urgent need for well-designed, adequately-powered, multi centre randomised controlled trials assessing the effects of weight reduction in persons with overweight or obesity on stroke occurrence.

The relationship between higher blood pressure and ischaemic, haemorrhagic stroke among Chinese and Caucasians: meta-analysis

BACKGROUND AND PURPOSE

Previous studies have suggested that blood pressure is a particularly important risk factor for stroke in Chinese, and that the magnitude of the effect may be greater than in Caucasians. We performed a meta-analysis in order to define the magnitude of the risk of stroke associated with hypertension among Chinese, and to compare the magnitude of this risk with Caucasians.

METHODS

We searched Medline from 1966 to 2004, plus Chinese Medical Literature databases from 1977 to 2003 for Caucasian and Chinese studies. Results were pooled using the random effects model, and heterogeneity and publication bias were checked.

RESULTS

For a 10 mmHg increase in systolic blood pressure, the pooled risk ratio was 1.44 [95% confidence interval (CI)] 1.39-1.51 for ischaemic stroke, and 1.5 (95% CI 1.45-1.57) for haemorrhagic stroke in Chinese, versus 1.19 (95% CI 1.15-1.23) for total stroke in Caucasians. The pooled odds ratio for hypertension measured dichotomously (defined as > or =160/95 mmHg) was 5.8 (95% CI 4.7-7.2) among Chinese versus 1.93 (95% CI 1.7-2.2) among Caucasians for ischaemic stroke; and 7.2 (95% CI 5.3-9.7) in Chinese versus 3.1 (95% CI 2.5-3.9) in Caucasians for haemorrhagic stroke.

CONCLUSION

The risk of stroke associated with hypertension is consistently and significantly greater in Chinese than Caucasians. This may help genetic epidemiologists to dissect the cause of stroke, and emphasizes the particular importance of hypertension control in the Chinese population.

Genetic variation at the growth hormone (GH1) and growth hormone receptor (GHR) loci as a risk factor for hypertension and stroke

An increased prevalence of both hypertension and cerebrovascular stroke is apparent in growth hormone (GH) deficiency whilst hypertension is a frequent complication in acromegaly. This has suggested a possible link between GH, stature and arterial function. Since the risk of both hypertension and stroke also appears to be inversely correlated with adult height, we have instigated an exploratory study to assess whether inter-individual variation in the genes encoding human growth hormone (GH1) and the GH receptor (GHR) might be associated with an increased risk of hypertension and stroke. GH1 promoter haplotypes were found to differ significantly not only between hypertensive patients (n = 111) and controls (n = 121) but also between stroke patients (n = 155) and controls (n = 158). Intriguingly, the association between GH1 promoter haplotype and risk of hypertension was much greater in females than in males. An inverse correlation between height and central systolic blood pressure was apparent in both hypertensive patients and normal controls but was much stronger in individuals carrying at least one GH1 promoter risk haplotype. The GH1 genotype therefore constitutes a risk factor for hypertension that interacts with stature. A strong association was found between the presence of at least one GH1 risk haplotype and a family history of stroke at an early age (odds ratio: 9.07, 95% confidence interval: 1.14-72.22). Three novel GH variants (Arg16His, Phe176Cys, Cys189Arg) were identified during the course of this study. Although two exhibited markedly reduced biological activity in vitro, their clinical significance remains unclear. No association was found between GHR genotype and either hypertension or stroke, nor was any interaction noted between GHR and GH1 genotypes in terms of a disease association. However, an association between GHRd3 genotype and hypertension was observed among stroke patients, particularly females. Elevated HDL was found to be a risk factor for hypertension in individuals lacking a copy of the GHRd3 allele. Weak associations with GHR genotype were also noted for peripheral systolic and diastolic blood pressure in hypertensive patients. Although the underlying mechanisms are still unclear, our findings are consistent with a complex relationship between height, hypertension, GH1 promoter haplotype, GHR polymorphism and the risk of stroke.

Diabetes and stroke: Part one—Risk factors and pathophysiology

Diabetes is a major risk factor for stroke and is associated with an increase in overall stroke mortality. The metabolic syndrome associated with insulin resistance is also a significant risk factor for stroke. The etiology of stroke in diabetics is frequently microvascular disease from fibrinoid necrosis, which causes small subcortical infarcts designated as lacunar strokes. Diabetics also have an increased incidence of large vessel intracranial vascular disease. Although strict control of blood sugar has not been shown to reduce the overall incidence of stroke in diabetics, careful management of other associated risk factors, particularly hypercholesterolemia and hypertension, are imperative for the prevention of stroke in diabetic patients.

Influence of childhood socioeconomic circumstances, height, and obesity on pulse pressure and systolic and diastolic blood pressure in older people

This study assesses the association of childhood socioeconomic circumstances, height, and obesity with components of blood pressure. We selected 4009 people representative of the Spanish population aged 60 years and older, and estimated systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure (PP) according to childhood social class, height, and obesity. No association was found between childhood social class and blood pressure. SBP showed an inverse gradient and DBP a direct gradient with height, although an independent association between height and DBP was found only in women. Stature was independently associated with increased DBP in women with central obesity, but there was no association between height and DBP in women without central obesity. Short stature was independently associated with increased PP. Body mass index and waist-to-hip ratio were independently associated with increased DBP in women, and waist-to-hip ratio was independently associated with increased PP in men, while waist circumference was independently associated with increased DBP and increased PP in women. These results do not support the assumed effect of socioeconomic circumstances in early life on blood pressure, which may depend on the context and/or study population. The relations observed between height and blood pressure support the hypothesis that PP could be a mediator of the association between short stature and increased cardiovascular risk. The relationship between obesity measures and components of blood pressure reinforces the recommendation to reduce body weight in order to reduce blood pressure.

Vascular risk factors in the Swiss population

BACKGROUND AND PURPOSE

Identification of the population at risk of stroke remains the best approach to assess the burden of cardiovascular morbidity and mortality.

METHODS

The prevalence of hypertension (HT), hypercholesterolemia (HCh), diabetes mellitus (DM), overweight (OW), obesity (OB), tobacco use (SM), and their combinations was examined in 4,458 Swiss persons (1,741 men and 2,717 women, mean age 57.8 +/- 15 years), who volunteered for the present survey.

RESULTS

OW was the most prevalent risk factor (50 %), followed by HT (47%), HCh (33%), SM (13 %) and DM (1.6 %). The proportion of persons without risk factors (RF) was 19.9%, with 1 RF 41.5%, 2 RF 33.8%, 3 RF 4%, and 4 RF 0.9%. OW was more prevalent in men than in women (53% vs. 41%, P=0.02). More men than women aged 41-50 years and 51-60 years had HT (49 % vs. 36%, P=0.01, and 52 % vs. 42%, P=0.02). The prevalence of HCh and DM did not show any sex-related differences. HT, OW and HCh were not only the most common single risk factors, but were also most likely to aggregate with each other.

CONCLUSIONS

The majority of Swiss people have one or two vascular risk factors. OW and HT are by far most common and are likely to aggregate with each other. A small modification of these two factors would reduce the incidence of stroke and myocardial infarction significantly.

Strategies for prevention and management of hypertension throughout life

Hypertension has been acknowledged as one of the greatest and established risk factors for cardiovascular diseases. In this special article, strategies for the prevention and management of hypertension throughout human’s life were discussed. Studies showing the relationship of birth weight and height increase in childhood to future blood pressure suggest that both environments during pregnancy and during childhood and adolescence are important to prevent hypertension. The promotion of a DASH (Dietary Approach to Stop Hypertension) dietary pattern, rich in fruits and vegetables, is important not only for treatment of high blood pressure but also for long-term prevention of blood pressure rise as well. Blood pressure measured in young adulthood can effectively predict long-term risks of cardiovascular and all-cause mortality, so population-wide primary prevention of high blood pressure for young adults is important. Recent large scale cohort studies confirmed that detection and evaluation of hypertension based mainly on systolic blood pressure remains the most practical and easy approach in the general population for young adult, middle-aged, and older men and women. Researchers in Asia are desired to establish high-quality epidemiologic evidences for Asian for the prevention and management of hypertension.

Low birth size and final height predict high sympathetic nerve activity in adulthood

OBJECTIVE

Being born small for gestational age (SGA) is associated with insulin resistance, hypertension and increased cardiovascular morbidity/mortality in adulthood. Sympathetic nerve hyperactivity is a well-known risk factor for cardiovascular disease mortality and is proposed to link insulin resistance with hypertension. The objective of this study was to test the hypothesis that sympathetic nerve activity is altered in individuals born SGA.

DESIGN

A cross-sectional, comparative study of 20 healthy adults (21-25 years old) born SGA (birth weight < -2SD score for healthy newborns) with normal and short stature, and 12 age, gender and body mass index matched individuals, born appropriate for gestational age (AGA) with normal stature.

METHODS

Direct recordings of resting sympathetic nerve activity to the muscle vascular bed (MSA) were obtained from the peroneal nerve posterior to the fibular head. Heart rate, respiration and blood pressure were recorded during the microneurographic session.

RESULTS

MSA was increased in both groups of young adults born SGA as compared to those born AGA (P < 0.05 and P < 0.005, respectively). In the combined study group MSA was inversely correlated to birth weight, length (r = -0.59, P < 0.001 and r = -0.69, P < 0.0005, respectively) and final adult height (r = -0.58; P < 0.001).

CONCLUSIONS

Being born SGA and achieving a short final height is associated with increased sympathetic nerve traffic. We suggest that the increase in sympathetic nerve traffic in young adults born SGA with normal and short stature may be the link between low birth size, hypertension and cardiovascular morbidity later in life.

IGF-I activity may be a key determinant of stroke risk--a cautionary lesson for vegans

IGF-I acts on vascular endothelium to activate nitric oxide synthase, thereby promoting vascular health; there is reason to believe that this protection is especially crucial to the cerebral vasculature, helping to ward off thrombotic strokes. IGF-I may also promote the structural integrity of cerebral arteries, thereby offering protection from hemorrhagic stroke. These considerations may help to explain why tallness is associated with low stroke risk, whereas growth hormone deficiency increases stroke risk--and why age-adjusted stroke mortality has been exceptionally high in rural Asians eating quasi-vegan diets, but has been declining steadily in Asia as diets have become progressively higher in animal products. There is good reason to suspect that low-fat vegan diets tend to down-regulate systemic IGF-I activity; this effect would be expected to increase stroke risk in vegans. Furthermore, epidemiology suggests that low serum cholesterol, and possibly also a low dietary intake of saturated fat--both characteristic of those adopting low-fat vegan diets--may also increase stroke risk. Vegans are thus well advised to adopt practical countermeasures to minimize stroke risk--the most definitive of which may be salt restriction. A high potassium intake, aerobic exercise training, whole grains, moderate alcohol consumption, low-dose aspirin, statin or policosanol therapy, green tea, and supplementation with fish oil, taurine, arginine, and B vitamins--as well as pharmacotherapy of hypertension if warranted--are other practical measures for lowering stroke risk. Although low-fat vegan diets may markedly reduce risk for coronary disease, diabetes, and many common types of cancer, an increased risk for stroke may represent an 'Achilles heel'. Nonetheless, vegans have the potential to achieve a truly exceptional 'healthspan' if they face this problem forthrightly by restricting salt intake and taking other practical measures that promote cerebrovascular health.

Socio-economic position and height in early adulthood

OBJECTIVES

To examine the relationship between socio-economic position and height in early adulthood.

METHOD

A representative probability sample of Australian households (part of the 1995 National Health Survey). Data were collected by face-to-face interviews. Socio-economic position was measured using occupation and family income. Participants comprised 9,577 Australian-born males and females aged 20-24 (n = 3,186), 25-29 (n = 3,184), and 30-34 (n = 3,207). Height was self-reported and operationalised in terms of mean height and 'short' stature (defined as 1 SD below mean height for each sex-age subgroup).

RESULTS

Graded, positive associations were found between occupation, family income, and height for males and females in each age cohort. Among males, mean height differences between blue-collar employees and professionals were 1.1 cm to 1.5 cm (depending on age-cohort), and for females, 1.6 cm to 2.1 cm. The corresponding height differences for males and females living in the least and most affluent families were 1.6 cm to 2.3 cm, and 1.0 cm to 2.5 cm, respectively. Persons in blue-collar jobs and those in low-income families were more likely to be classified as 'short'.

CONCLUSIONS AND IMPLICATIONS

Estimates of mortality risk associated with short stature suggest that these height differences translate to about a 2-5% increased risk of death for the most disadvantaged groups. Given that socioeconomic height differences in adulthood have their genesis in the formative stages of biological and social development, public health intervention efforts need to focus on early life exposures and environments. The greatest reduction in height inequalities, and by extension health inequalities, is likely to flow from macro-level public policies to alleviate poverty and minimise the social and economic divide.

Height in young adulthood and risk of death from cardiorespiratory disease: a prospective study of male former students of Glasgow University, Scotland

To investigate the association between height in young, socially homogeneous males and cause-specific mortality, the authors conducted a prospective study of 8,361 male former students who underwent medical examinations while attending Glasgow University, Scotland, from 1948 to 1968. The mean age at examination was 20.5 (range, 16.1-30.0) years. The median follow-up time was 41.3 years. There were 863 deaths. In Cox proportional hazards modeling, there was no association between height and all-cause mortality with age-adjusted hazard ratios per 10-cm increase in height (hazard ratio = 0.92, 95% confidence interval: 0.83, 1.02). Height was inversely associated with all cardiovascular disease and coronary heart disease mortality, with hazard ratios per 10-cm increase in height of 0.78 (95% confidence interval: 0.66, 0.93) and 0.76 (95% confidence interval: 0.62, 0.93), respectively. Sizeable inverse associations with stroke and respiratory disease were also found, although these did not reach conventional levels of significance. There was no association with cancer or noncardiorespiratory disease mortality. There was a positive, although nonsignificant, association between height and mortality from aortic aneurysm. Controlling for confounding variables had little effect on these results. The findings suggest that factors operating in early life, and which influence height, also influence future cardiovascular health in men.

Relationship of volume of lesion to length of hospital stay and outcome at one year in stroke patients

The aim of this study was to investigate the relationship between the volume of lesion (VOL) in patients with stroke and the associated length of hospital stay (LOS), as well as longer-term functional outcome. Computerised tomography (CT) scans were used to measure the volume, region and type of lesion, volume being measured by planimetry. LOS and other patient details were obtained from the Dundee Stroke Database. The total LOS was associated with the VOL on univariate analysis (p = 0.004) and after adjustment for the other variables (p = 0.006) due to a larger lesion being associated with longer stay in hospital. Patient follow-up confirmed that the VOL was also highly significant when related to functional outcome measures of impairment, disability and handicap at one year, as determined by Orgogozo (p = 0.03), Barthel (p < 0.01) and Rankin scores (p < 0.01) respectively. The VOL is related to the length of stay in hospital and outcome at one year. This is of particular interest with the increasing use of thrombolysis and development of neuroprotectant agents designed to limit VOL.

The incidence and aetiology of stroke in the Caerphilly and Speedwell Collaborative Studies II: risk factors for ischaemic stroke

Reduction of stroke burden requires preventive interventions targeted at important risk factors. This report presents the analysis of risk factors for ischaemic stroke from a representative cohort of middle aged men from South Wales and south-west England. Data on risk factors were collected through validated questionnaires and physical and clinical measurements. Details of possible cerebrovascular events were retrieved, classified into ischaemic, haemorrhagic and uncertain subtypes, and validated. The ratio of definite ischaemic to definite haemorrhagic strokes was calculated. This showed that the vast majority of strokes of unknown subtype were likely to ischaemic. After exclusion of known haemorrhagic strokes and subarrachnoid haemorrhages the remaining strokes were labelled ischaemic. Hazard ratios for possible risk factors were calculated for all ischaemic, and for fatal and non-fatal strokes. There were 293 ischaemic strokes. Statistically significant age-adjusted hazard ratios were: 1.50 (95% confidence interval 1.16-1.95) for being in a manual social class, 1.82 (1.24-2.67) if smoking >15 cigarettes/d at enrollment, 1.19 (1.13-1.24) and 1.23 (1.14-1.34) per 10 mmHg increase in systolic and diastolic blood pressure, respectively, 0.67 (0.46-0.96) for the top quintile high density lipoprotein-cholesterol:cholesterol ratio compared to the bottom quintile, 2.04 (1.40-2.99) for presence of angina, 3.90 (2.01-7.58) for presence of atrial fibrillation, and 3.35 (1.90-5.80) for presence of diabetes. Risk factors were more strongly associated with fatal than non-fatal strokes. Multivariate analyses revealed that, while there was some attenuation of the effect of social class, angina and elevated BP, the risks from atrial fibrillation and diabetes were increased.

Stroke: epidemiology, clinical picture, and risk factors--Part I of III

The aim of this review is to present the current knowledge regarding stroke. It will appear in three parts (in part II the pathogenesis, investigations, and prognosis will be presented, while part III will consist of the management and rehabilitation). In the current part (I) the definitions of the clinical picture are presented. These include: amaurosis fugax, vertebrobasilar transient ischemic attack, and stroke (with good recovery, in evolution and complete). The role of the following risk factors is discussed in detail: age, gender, ethnicity, heredity, hypertension, cigarette smoking, hyperlipidemia, diabetes mellitus, obesity, fibrinogen and clotting factors, oral contraceptives, erythrocytosis and hematocrit level, prior cerebrovascular and other diseases, physical inactivity, diet and alcohol consumption, illicit drug use, and genetic predisposition. In particular, regarding the carotid arteries, the following characteristics are analyzed: atheroma, carotid plaque echomorphology, carotid stenosis, presence of ulcer, local variations in surface deformability, pathological characteristics, and dissection. Finally the significance of the cerebral collateral circulation and the conditions predisposing to cardioembolism and to cerebral hemorrhage are presented.

Height and risk of death among men and women: aetiological implications of associations with cardiorespiratory disease and cancer mortality

OBJECTIVES

Height is inversely associated with cardiovascular disease mortality risk and has shown variable associations with cancer incidence and mortality. The interpretation of findings from previous studies has been constrained by data limitations. Associations between height and specific causes of death were investigated in a large general population cohort of men and women from the West of Scotland.

DESIGN

Prospective observational study.

SETTING

Renfrew and Paisley, in the West of Scotland.

SUBJECTS

7052 men and 8354 women aged 45-64 were recruited into a study in Renfrew and Paisley, in the West of Scotland, between 1972 and 1976. Detailed assessments of cardiovascular disease risk factors, morbidity and socioeconomic circumstances were made at baseline.

MAIN OUTCOME MEASURES

Deaths during 20 years of follow up classified into specific causes.

RESULTS

Over the follow up period 3347 men and 2638 women died. Height is inversely associated with all cause, coronary heart disease, stroke, and respiratory disease mortality among men and women. Adjustment for socioeconomic position and cardiovascular risk factors had little influence on these associations. Height is strongly associated with forced expiratory volume in one second (FEV1) and adjustment for FEV1 considerably attenuated the association between height and cardiorespiratory mortality. Smoking related cancer mortality is not associated with height. The risk of deaths from cancer unrelated to smoking tended to increase with height, particularly for haematopoietic, colorectal and prostate cancers. Stomach cancer mortality was inversely associated with height. Adjustment for socioeconomic position had little influence on these associations.

CONCLUSION

Height serves partly as an indicator of socioeconomic circumstances and nutritional status in childhood and this may underlie the inverse associations between height and adulthood cardiorespiratory mortality. Much of the association between height and cardiorespiratory mortality was accounted for by lung function, which is also partly determined by exposures acting in childhood. The inverse association between height and stomach cancer mortality probably reflects Helicobacter pylori infection in childhood resulting in--or being associated with--shorter height. The positive associations between height and several cancers unrelated to smoking could reflect the influence of calorie intake during childhood on the risk of these cancers.

Income, educational level and body height

The relation between adult body height and two socio-economic factors (income and educational level) was studied in a large, ethnically homogenous population. In the period 1980-1983 all persons aged 40-54 years (born 1926-1941) in two Norwegian counties were invited to a cardiovascular screening. Ninety per cent (or 38162 persons) of those invited attended and had their height measured. Information concerning income and education was available at an individual level from the 1980 national census. Strong, positive relations were found between mean body height and the socio-economic factors, relations that probably are due to conditions during growth influencing both height, attained education and income abilities. The difference between highest and lowest educational class was 3.3 cm in men and 3.2 cm in women, and between highest and lowest income group 3.5 cm in men and 4.2 cm in women. These differences could not be explained by the strong cohort effect of increasing height in the successive birth cohorts from 1926 to 1941 which also was evident. It should be emphasized that height only could explain a small fraction of the variance in the socio-economic factors and is thus not a usable indicator of an individual's socio-economic status. However, it might contribute with important information concerning social inequalities in groups or population.

Are risk factors for stroke and coronary disease the same?

Many risk factors operate in both coronary heart disease and stroke, especially ischaemic stroke--age, sex, social class, blood pressure, pre-existing vascular disease (angina, myocardial infarction, cardiac failure, diabetes and peripheral vascular disease, transient ischaemic attack and stroke), atrial fibrillation and fibrinogen, smoking, alcohol and height. Total cholesterol has also recently been recruited to this list. The various mechanisms involved in stroke and its subtypes and the epidemiological problems in evaluating aetiological factors in stroke make the comparison with coronary heart disease more difficult. The recent discrepancy between much of the epidemiology and the clinical trials evaluating the role of lipids in stroke has spurred the systematic review (meta-analysis) of major prospective observational studies. These will provide a clearer assessment about the quantitative comparison of some of the more important risk factors for stroke and coronary heart disease in the near future.

Inverse relation between height and cardiovascular mortality in men during 30-year follow-up

Results from a socioeconomically homogenous population of middle-aged men demonstrate that body height predicts total, and especially cardiovascular, mortality over a 30-year follow-up, independent of traditional risk factors. The results suggest that every 5-cm increase in height is associated with decline of cardiovascular mortality risk by 18%.