Search PubMed⌕ Search

Biomedical subjects

G Davey Smith

Publications and source records attributed to G Davey Smith.

At least 19 recordsLinked to original sources
PubMed1998

Mortality differences between black and white men in the USA: contribution of income and other risk factors among men screened for the MRFIT. MRFIT Research Group. Multiple Risk Factor Intervention Trial.

BACKGROUND: Studies of underlying differences in adult mortality between black and white individuals in the USA have been constrained by limitations of data or small study size. We investigated the extent to which differences in socioeconomic position between black and white men contribute to differences in all-cause and cause-specific mortality. METHODS: 361,662 men were screened for the Multiple Risk Factor Intervention Trial between 1973 and 1975, in 22 sites. Median family income of households by zipcode (postal) area of residence was available for 20,224 black and 300,685 white men as well as data on age, cigarette smoking, blood pressure, serum cholesterol, previous heart attack, and treatment for diabetes. We classified deaths during 16 years of follow-up into specific causes and compared differences in death rates between black men and white men, before and after adjustment for differences in income and other risk factors. FINDINGS: Age-adjusted relative risk of death (black vs white) was 1.47 (95% CI 1.42-1.53). Adjustment for diastolic blood pressure, serum cholesterol, cigarette smoking, medication for diabetes, and previous admission to hospital for heart attack decreased the relative risk to 1.40 (1.35-1.46). Adjustment for income but not the other risk factors decreased the risk to 1.19 (1.14-1.24) and adjustment for other risk factors did not alter this estimate. For cardiovascular death, relative risk on adjustment for income was decreased from 1.36 to 1.09; for cancer from 1.47 to 1.25; and for non-cardiovascular and non-cancer deaths from 1.71 to 1.26. For some specific causes of death, including prostate cancer, myeloma, and hypertensive heart disease, the higher death rates among black men did not seem to reflect differences in income. Rates of death for suicide and melanoma were lower among black than white men, as were those for coronary heart disease after adjustment for income. INTERPRETATION: Socioeconomic position is the major contributor to differences in death rates between black and white men. Differentials in mortality from some specific causes do not simply reflect differences in income, however, and more detailed investigations are needed of how differences are influenced by environmental exposures, lifetime socioeconomic conditions, lifestyle, racism, and other sociocultural and biological factors.

Adult↗
PubMed1998

Childhood energy intake and adult mortality from cancer: the Boyd Orr Cohort Study.

OBJECTIVE: To examine the relation between energy intake in childhood and adult mortality from cancer. STUDY DESIGN: Cohort study. SETTING: 16 rural and urban centres in England and Scotland. SUBJECTS: 3834 people who took part in Lord Boyd Orr's Carnegie survey of family diet and health in prewar Britain between 1937 and 1939 who were followed up with the NHS, central register. Standardised methods were used to measure household dietary intake during a one week period. MAIN OUTCOME MEASURES: Cancer mortality. RESULTS: Significant associations between childhood energy intake and cancer mortality were seen when the confounding effects of social variables were taken into account in proportional hazards models (relative hazard for all cancer mortality 1.15 (95% confidence interval 1.06 to 1.24), P = 0.001, for every MJ increase in adult equivalent daily intake in fully adjusted models). This effect was essentially limited to cancers not related to smoking (relative hazard 1.20; 1.07 to 1.34; P = 0.001), with similar effects seen in men and women. CONCLUSION: This positive association between childhood energy intake and later cancer is consistent with animal evidence linking energy restriction with reduced incidence of cancer and the association between height and human cancer, implying that higher levels of energy intake in childhood increase the risk of later development of cancer. This evidence for long term effects of early diet confirm the importance of optimal nutrition in childhood and suggest that the unfavourable trends seen in the incidence of some cancers may have their origins in early life.

Adolescent↗
PubMed1998

The health effects of major organisational change and job insecurity.

Since August 1988 an increasing proportion of the executive functions of government in the United Kingdom have been devolved to executive agencies. Transfer to an executive agency involves a period of uncertainty during which the options of elimination or transfer to the private sector are considered, followed by a marked change in management style and further periods of uncertainty when the agency's function is reconsidered for transfer to the private sector. This paper examines the effects of this major organisational change and consequent job insecurity on the health status of a cohort of 7419 white-collar civil servants by comparing groups either exposed to or anticipating exposure to this stressor, with controls experiencing no change. Compared with controls, men both already working in and anticipating transfer to an executive agency experienced significant increases in health self-rated as "average or worse", longstanding illness, adverse sleep patterns, mean number of symptoms in the fortnight before questionnaire completion, and minor psychiatric morbidity. Significant relative increases in body mass index were seen in both exposure groups while exposure to agency status was also associated with significant relative increases in blood pressure. Health-related behaviours, where they differed between exposure and control groups, tended to favour those in the exposure groups. Compared with controls, women in both exposure groups reported small increases in most self-reported morbidity measures and most clinical measurements, accompanied by slight beneficial changes in some health-related behaviours and small adverse changes in others. Significant relative increases were seen in mean number of symptoms, and ischaemia among women anticipating exposure and in body mass index among those exposed to agency status. Policy makers should be aware of the wider consequences of job insecurity when considering the efficiency of changes in employment policy.

Adult↗
PubMed1998

Childhood obesity and adult cardiovascular mortality: a 57-y follow-up study based on the Boyd Orr cohort.

Few studies have examined associations between childhood overweight and adult disease. We examined the relation between BMI measured in childhood and adult all-cause and cardiovascular mortality in a 57-y follow-up of a cohort study based on the Carnegie (Boyd Orr) Survey of Family Diet and Health in prewar Britain (1937-1939). Complete baseline and follow-up data were available for 1165 males and 1234 females who were aged between 2 y and 14 y 9 mo when they were examined. All-cause and cardiovascular mortality were associated with higher childhood BMIs. Compared with those with BMIs between the 25th and 49th centiles, the hazard ratio (95% CI) for all-cause mortality in those above the 75th BMI centile for their age and sex was 1.5 (1.1, 2.2) and for ischemic heart disease it was 2.0 (1.0, 3.9). There was also a suggestion of a nonlinear association with overall mortality; those in the 25-49th centile of the BMI distribution had the lowest mortality rates. The linear associations may be due in part to the tracking of BMI between childhood and adulthood. High BMI in adults is known to be associated with raised blood pressure and abnormal lipid profiles. The relative contributions of adult and childhood overweight to the observed mortality patterns are uncertain. From the public health perspective, strategies aimed at reducing weight in childhood are important but may only affect adult health if such weight reduction persists into adulthood.

Adolescent↗
PubMed1998

Childhood leg length and adult mortality: follow up of the Carnegie (Boyd Orr) Survey of Diet and Health in Pre-war Britain.

OBJECTIVE: To investigate the relation between childhood height, its components--leg length and trunk length--and mortality in adulthood. DESIGN: Cohort study based on the Carnegie (Boyd Orr) Survey of diet and health in pre-war Britain, 1937-9. SETTING: The 14 centres in England and Scotland that participated in the Carnegie Survey and where children were examined. Scottish centres: Aberdeen, Dundee, West Wemyss, Coaltown of Wemyss, Hopeman, Methlick, Tarves, Barthol Chapel. English Centres: Liverpool, York-shire, Barrow in Furness, Wisbech, Fulham, and Bethnal Green. SUBJECTS: 2990 boys and girls aged between 2 years and 14 years 9 months when they were examined in 1937-9. These children were drawn from 1134 families who underwent a one week assessment of family diet and home circumstances. Of these, 2547 (85%) have been traced and flagged using the NHS Central Register. MAIN OUTCOME MEASURES: Age adjusted overall, coronary heart disease, and cancer mortality in men and women in relation to age and sex specific z scores for height, leg length, and trunk length. All analyses were adjusted for the possible confounding effects of childhood and adult socioeconomic circumstances and childhood diet. RESULTS: Leg length was the component of childhood height most strongly associated with socioeconomic and dietary exposures. There was no significant relation between childhood height and overall mortality. Height-mortality relations were observed in relation to both coronary heart disease (CHD) and cancer. Leg length was the component of height most strongly related to cause specific mortality. In men and women CHD mortality increased with decreasing childhood leg length. Men in the lowest leg length quintile had a relative risk (RR) of 2.5 (95% CI 1.0 to 6.2) compared to those with the longest legs (linear trend p = 0.14). Similarly, women in the lowest leg length quintile had a RR of 3.9 (95% CI 0.8 to 19.0; linear trend p < 0.01). Adjustment for childhood and adult socioeconomic circumstances had little effect on these trends. In men, but not women, those who as children had long legs experienced increased cancer mortality. The significant relations between anthropometry and both CHD and cancer mortality were restricted to those aged < 8 years when measured. CONCLUSIONS: These findings suggest that adverse diet and living conditions in childhood, for which leg length seems to be a particularly sensitive indicator, are associated with increased risk of CHD in adulthood and possibly reduced cancer risk. It is likely that these influences operate after birth, during the first few years of life.

Adolescent↗
PubMed1998

Education and occupational social class: which is the more important indicator of mortality risk?

STUDY OBJECTIVES: In the UK, studies of socioeconomic differentials in mortality have generally relied upon occupational social class as the index of socioeconomic position, while in the US, measures based upon education have been widely used. These two measures have different characteristics; for example, social class can change throughout adult life, while education is unlikely to alter after early adulthood. Therefore different interpretations can be given to the mortality differentials that are seen. The objective of this analysis is to demonstrate the profile of mortality differentials, and the factors underlying these differentials, which are associated with the two socioeconomic measures. DESIGN: Prospective observational study. SETTING: 27 work places in the west of Scotland. PARTICIPANTS: 5749 men aged 35-64 who completed questionnaires and were examined between 1970 and 1973. FINDINGS: At baseline, similar gradients between socioeconomic position and blood pressure, height, lung function, and smoking behaviour were seen, regardless of whether the education or social class measure was used. Manual social class and early termination of full time education were associated with higher blood pressure, shorter height, poorer lung function, and a higher prevalence of smoking. Within education strata, the graded association between smoking and social class remains strong, whereas within social class groups the relation between education and smoking is attenuated. Over 21 years of follow up, 1639 of the men died. Mortality from all causes and from three broad cause of death groups (cardiovascular disease, malignant disease, and other causes) showed similar associations with social class and education. For all cause of death groups, men in manual social classes and men who terminated full time education at an early age had higher death rates. Cardiovascular disease was the cause of death group most strongly associated with education, while the non-cardiovascular non-cancer category was the cause of death group most strongly associated with adulthood social class. The graded association between social class and all cause mortality remains strong and significant within education strata, whereas within social class strata the relation between education and mortality is less clear. CONCLUSIONS: As a single indicator of socioeconomic position occupational social class in adulthood is a better discriminator of socioeconomic differentials in mortality and smoking behaviour than is education. This argues against interpretations that see cultural--rather than material--resources as being the key determinants of socioeconomic differentials in health. The stronger association of education with death from cardiovascular causes than with other causes of death may reflect the function of education as an index of socioeconomic circumstances in early life, which appear to have a particular influence on the risk of cardiovascular disease.

Adult↗
PubMed1998

Socioeconomic differentials in mortality among men within Great Britain: time trends and contributory causes.

STUDY OBJECTIVE: To assess the size of mortality differentials in men by social class in Scotland as compared with England and Wales, and to analyse the time trends in these differentials. SUBJECTS: Men from England and Wales and Scotland around each census from 1951 to 1981. METHODS: Poisson regression analysis was used to calculate relative indices of inequality for disease specific and all cause mortality as a measure of mortality differentials between social classes. This measure is not dependent on the size of the social class groups, so it can be used to compare the magnitude of differentials over time periods during which the relative sizes of social class groups change. MAIN RESULTS: While overall death rates were higher in Scotland than in England and Wales around the 1951, 1961, and 1971 censuses the relative indices of inequality indicated smaller mortality differences between social classes in Scotland. Inequality, as indexed by the relative index of inequality, increased over time in both Scotland and England and Wales, but to a greater degree in Scotland, resulting in greater social class mortality differentials for Scotland in 1981 (the relative index of inequality increased from 1.40 to 2.43 for England and Wales, and from 1.22 to 2.57 for Scotland between 1951 and 1981). This greater increase in the magnitude of inequalities in all cause mortality in Scotland seemed to result from increasing social class differentials in cardiovascular disease, accidents and external causes, and "all other causes of death". Examining the trends in overall death rates, it seems that the greater increase in social class differences in Scotland occurred because of the greater decrease in death rates among the privileged social groups, in combination with a smaller decrease (or a greater increase) in the death rates in the lower social class groups. CONCLUSIONS: This study has shown that trends in mortality and in inequalities in mortality differ within Great Britain. Although death rates were higher in Scotland than in England and Wales, smaller mortality differentials by social class were found in Scotland over the period 1951 to 1971. By 1981, however, social class mortality differentials were greater in Scotland than in England and Wales. The greater increase in the social class differentials over time in Scotland, may have contributed to the worsening overall mortality profile in Scotland as compared with England and Wales that occurred between 1971 and 1981.

Adolescent↗
PubMed1997

Birth weight of offspring and mortality in the Renfrew and Paisley study: prospective observational study.

OBJECTIVE: To investigate the association between birth weight of offspring and mortality among fathers and mothers in the west of Scotland. DESIGN: Prospective observational study. PARTICIPANTS: 794 married couples in Renfrew district of the west of Scotland. MAIN OUTCOME MEASURES: Mortality from all causes and from cardiovascular disease over 15 year follow up. RESULTS: Women who had heavier babies were taller, had higher body mass index and better lung function, and were less likely to be smokers than mothers of lighter babies. Fathers of heavier babies were taller and less likely to be smokers than fathers of lighter babies. Mortality was inversely related to offspring's birth weight for both mothers (relative rate for a 1 kg lower birth weight 1.82 (95% confidence interval 1.23 to 2.70)) and fathers (relative rate 1.35 (1.03 to 1.79)). For mortality from cardiovascular disease, inverse associations were seen for mothers (2.00 (1.18 to 3.33)) and fathers (1.52 (1.03 to 2.17)). Adjustment for blood pressure, plasma cholesterol, body mass index, height, social class, area based deprivation category, smoking, lung function, angina, bronchitis, and electrocardiographic evidence of ischaemia had little effect on these risk estimates, although levels of statistical significance were reduced. CONCLUSIONS: Birth weight of offspring was related inversely to mortality, from all causes and cardiovascular disease, in this cohort. The strength of this association was greater than would have been expected by the degree of concordance of birth weights across generations, but an extensive range of potential confounding factors could not account for the association. Mortality is therefore influenced by a factor related to birth weight that is transmissible across generations.

Birth Weight↗
PubMed1997

Bias in meta-analysis detected by a simple, graphical test.

OBJECTIVE: Funnel plots (plots of effect estimates against sample size) may be useful to detect bias in meta-analyses that were later contradicted by large trials. We examined whether a simple test of asymmetry of funnel plots predicts discordance of results when meta-analyses are compared to large trials, and we assessed the prevalence of bias in published meta-analyses. DESIGN: Medline search to identify pairs consisting of a meta-analysis and a single large trial (concordance of results was assumed if effects were in the same direction and the meta-analytic estimate was within 30% of the trial); analysis of funnel plots from 37 meta-analyses identified from a hand search of four leading general medicine journals 1993-6 and 38 meta-analyses from the second 1996 issue of the Cochrane Database of Systematic Reviews. MAIN OUTCOME MEASURE: Degree of funnel plot asymmetry as measured by the intercept from regression of standard normal deviates against precision. RESULTS: In the eight pairs of meta-analysis and large trial that were identified (five from cardiovascular medicine, one from diabetic medicine, one from geriatric medicine, one from perinatal medicine) there were four concordant and four discordant pairs. In all cases discordance was due to meta-analyses showing larger effects. Funnel plot asymmetry was present in three out of four discordant pairs but in none of concordant pairs. In 14 (38%) journal meta-analyses and 5 (13%) Cochrane reviews, funnel plot asymmetry indicated that there was bias. CONCLUSIONS: A simple analysis of funnel plots provides a useful test for the likely presence of bias in meta-analyses, but as the capacity to detect bias will be limited when meta-analyses are based on a limited number of small trials the results from such analyses should be treated with considerable caution.

Bias↗