Search PubMed⌕ Search

Biomedical subjects

G D Smith

Publications and source records attributed to G D Smith.

At least 163 records · Page 9Linked to original sources
PubMed1999

Income and health: what is the nature of the relationship?

The aim of this article is to examine the relationship between income and morbidity, both before and after controlling for other socio-economic variables. We use data from the Health and Lifestyle Survey (first wave), a national sample survey of adults, aged 18 upwards, in England, Wales and Scotland, conducted in 1984-1985. In total, 9003 interviews were achieved. We examine the shape of the relationship between household equivalised income and height, waist-hip ratio, respiratory function (FEV1), malaise, limiting longterm illness. These indices of morbidity, both self-reported and measured, are approximately linearly related to the logarithm of income, in all except very high and low incomes (this means that increasing income is associated with better health, but that there are diminishing returns at higher levels of income). A doubling of income is associated with a similar effect on health, regardless of the point at which this occurs, providing this is within the central portion (10-90%) of the income distribution. The effect of income on the health measures is comparable to that of the other socio-economic variables in combination. The shape of the relationship found between income and health is compatible with worse health in countries with greater income inequality, without the need to postulate any direct effect of income inequality itself.

Adult↗
PubMed1999

The health impact of smoking in manual and non-manual social class men and women: a test of the Blaxter hypothesis.

Blaxter has hypothesized that harmful behavioral habits like smoking have a greater impact on health in the non-manual than in the manual social classes, possibly because other adverse exposures have a more important role in the manual social classes. However, the outcome measure used was a composite measure of physiological indices of morbidity and the relevance of this to other health problems is uncertain. We have therefore investigated the effect of smoking on mortality, to test whether the risk of death associated with smoking differs between manual and non-manual social classes. Data on 6831 men and 7993 women, aged 45-64 when screened in the Renfrew and Paisley study, a large prospective observational study in the West of Scotland, have been analyzed. All cause mortality rate ratios for smokers compared with never smokers have been calculated within manual and non-manual social classes. Although the age adjusted rate ratios are slightly higher among the non-manual men and women (2.19 [1.83-2.61] versus 1.92 [1.71-2.17] for non-manual and manual men respectively, and 1.75 [1.54-1.99] versus 1.65 [1.50-1.82] for non-manual and manual women), this difference between social classes is not statistically significant (p-values for test of difference 0.26 and 0.47 for men and women respectively). When additionally adjusted for other risk factors, cardiorespiratory symptoms and deprivation, this picture remained the same (p-values for test of difference are 0.41 and 0.50 for men and women respectively). Similar results were found when the cohort was divided by deprivation categories rather than social classes or when smoking related mortality rather than mortality from all causes was used as the outcome measure. We therefore conclude that the health impact of smoking is similar in each socio-economic group. The relative health improvement consequent on smoking cessation is thus similar in different socio-economic groups.

Aged↗
PubMed1999

Preparation of a microcrystalline suspension formulation of Lys(B28)Pro(B29)-human insulin with ultralente properties.

The monomeric analogue, Lys(B28)Pro(B29)-human insulin (LysPro), has been crystallized using similar conditions employed to prepare extended-acting insulin ultralente formulations. In the presence of zinc ions, sodium acetate and sodium chloride, but without phenolic preservative, LysPro surprisingly forms small rhombohedral crystals with similar morphology to human insulin ultralente crystals with a mean particle size of 20 +/- 1 microm. X-ray powder diffraction studies on the LysPro crystals prior to dilution in ultralente vehicle ([NaCl] = 1.2 M) revealed the presence of T(3)R(3)(f) hexamers. Consistent with human insulin ultralente preparations, LysPro crystals formulated as an ultralente suspension ([NaCl] = 0. 12 M) contain T(6) hexamers indicating that a conformational change occurs in the hexamer units of the crystals upon dilution of the salt concentration. The pharmacological properties of subcutaneously administered ultralente LysPro (ULP) were compared to ultralente human insulin (UHI) using a conscious dog model (n = 5) with glucose levels clamped at basal. There were no statistically significant differences between the kinetic and dynamic responses of ULP compared to UHI [C(max) (ng/mL): 3.58 +/- 0.76, ULP and 3.61 +/- 0. 66, UHI; T(max) (min): 226 +/- 30, ULP and 185 +/- 42, UHI; R(max) (mg/kg min): 11.2 +/- 1.9, ULP and 13.3 +/- 2.0, UHI; and T(Rmax) (min): 336 +/- 11, ULP and 285 +/- 57, UHI]. Although the Pro to Lys sequence inversion destabilizes insulin self-assembly and greatly alters the time action of soluble LysPro preparations, this modification has now been found neither to prevent the formation of ultralente crystals in the absence of phenolics nor to compromise the protracted activity of the insulin analogue suspension.

Animals↗
PubMed1999

The long-term effect of advice to eat more fish on blood pressure in men with coronary disease: results from the diet and reinfarction trial.

BACKGROUND: Systematic reviews of fish and fish oil supplements have reported modest reductions in blood pressure (BP). Many of the trials included in these reviews used high doses of fish oil and most were of short duration. METHOD: Between 1983 and 1987 2033 men under the age of 70, who had recently suffered a myocardial infarction, were enrolled in a 2-year trial of dietary advice-the Diet and Reinfarction Trial (DART). Participants were randomised in a factorial design to receive intensive advice to eat more fish, less fat or more fibre. Those men randomised to receive fish advice were encouraged to eat two portions of fatty fish each week. Intake of eicosapentaenoic acid was 0.33 g per day in the fish advice arm and 0.10 g per day in men not given fish advice. RESULTS: The difference in systolic BP in the fish advice arm, adjusted for age and BP at baseline, was -0.61 mm Hg (95% CI -2.15, 0.92) at 6 months and 0.40 mm Hg (95% CI -1.33, 2.13) at 2 years. The difference in diastolic BP in the fish advice arm, adjusted for age and BP at baseline, was -0.50 mm Hg (95% CI -1.47, 0.46) at 6 months and 0.19 mm Hg (95% CI -0.88, 1.26) at 2 years. CONCLUSIONS: Advice to eat modest amounts of fish has little effect on BP in men with coronary disease.

Aged↗
PubMed1999

The 'number need to treat': does it help clinical decision making?

The number needed to treat (NNT) is an increasingly popular way of presenting the effects of treatment. However, the NNT varies markedly depending on the baseline risk of patients, the outcome considered, and the clinical setting. Furthermore geographic and secular trends make the NNT unstable between places and over time. Particular caution is needed in deriving the NNT from pooled absolute risk differences in meta-analysis. In general, the NNT should be calculated by applying the relative risk reduction on treatment estimated by trials or meta-analysis to populations of specified absolute high, average or low risk to illustrate a range of possible NNTs.

Antihypertensive Agents↗
PubMed1999

Association of medical, physiological, behavioural and socio-economic factors with elevated mortality in men of Irish heritage in West Scotland.

BACKGROUND: Men with patrilineal Irish descent from the immigrations of the nineteenth and twentieth centuries have higher death rates from 'all-causes' and, specifically, cardiovascular disease (CVD) than the general population of the West of Scotland. METHODS: A total of 5766 male employees from 27 workplace settings were examined between 1970 and 1973. Surname analysis identified 15 per cent of these men as of patrilineal Irish heritage. For those who have since died, the date and cause of death was obtained. Cox's proportional hazards model was used to compare the mortality risk of those with Irish and non-Irish surnames, and to investigate established medical, physiological, behavioural and socio-economic risk factors (acting in early and later life) as possible explanations for this excess mortality. RESULTS: The relative risk of death from all causes for the Irish of 1.26 (95 per cent confidence interval (CI) (1.12, 1.43)) was reduced to 1.12 (95 per cent CI (0.99, 1.26)) by including established risk factors in the model. The relative risk of CVD mortality of 1.51 (95 per cent CI (1.29, 1.77)) for the Irish was reduced to 1.35 (95 per cent CI (1.14, 1.58)) by the same adjustments. The elevated all-cause mortality of the Irish was mainly attributable to cardiovascular deaths. CONCLUSIONS: Cigarette smoking was only able to 'explain' a small amount of the excess all-cause and CVD mortality of men with patrilineal Irish descent. Relative deprivation during childhood and adulthood contributed to the high Irish mortality. However, there remains a substantial excess of premature deaths among Irish men which is unaccounted for by established risk factors.

Adult↗
PubMed1999

When does cardiovascular risk start? Past and present socioeconomic circumstances and risk factors in adulthood.

STUDY OBJECTIVES: To compare associations of childhood and adult socioeconomic position with cardiovascular risk factors measured in adulthood. To estimate the effects of adult socioeconomic position after adjustment for childhood circumstances. DESIGN: Cross sectional survey, using the relative index of inequality method to compare socioeconomic differences at different life stages. SETTING: The Whitehall II longitudinal study of men and women employed in London offices of the Civil Service at study baseline in 1985-88. PARTICIPANTS: 4774 men and 2206 women born in the period 1930-53 who were administered questions on early socioeconomic circumstances. MAIN RESULTS: Adult occupational position (employment grade) was inversely associated (high status-low risk) with current smoking and leisure time physical inactivity, with waist/height, and with metabolic risk factors HDL cholesterol, triglycerides, post-load glucose and fibrinogen. Associations of these variables with childhood socioeconomic position (father's Registrar General Social Class) were weaker or absent, with the exception of smoking in women. Childhood social position was associated with adult weight in both sexes and with current smoking, waist/height, HDL cholesterol and fibrinogen in women. Height, a measure of health capital or constitution, was weakly linked with father's social class and more strongly linked with own employment grade. The combination of childhood disadvantage (low father's class) together with a low status clerical occupation in men was particularly associated with higher body mass index as an adult (interaction test p < 0.001). Adjustment for earlier socioeconomic position--using father's class and own education level simultaneously--did not weaken the effects of adult socioeconomic position, except in the case of smoking in women, when the grade effect was reduced by 59 per cent. CONCLUSIONS: Cardiovascular risk factors in adulthood were in general more strongly related to adult than to childhood socioeconomic position. Among women but not men there was a strong but unexplained link between father's class and adult smoking habit. In both sexes degree of obesity was associated with both childhood and adulthood social position. These findings suggest that the socially patterned accumulation of health capital and cardiovascular risk begins in childhood and continues, according to socioeconomic position, during adulthood.

Adult↗
PubMed1999

Similarities in the epidemiology of neural tube defects and coronary heart disease: is homocysteine the missing link?

It is hypothesised that a single aetiological pathway could explain both the strong ecological association between the birth prevalence of neural tube defects (NTD) and coronary heart disease (CHD) mortality and the potential efficacy of dietary measures, especially increased folic acid intake, in their prevention. The epidemiological similarities between NTD and CHD are strong and consistent suggesting that the relation is real rather than artefactual. It is suggested that this epidemiological association reflects a shared aetiology arising from the role of disturbed homocysteine metabolism in the pathogenesis of both conditions. Current public health measures designed to increase the intake of periconceptional folic acid in women, reinforced by a broadening of this policy to target both sexes throughout life, will (if successful) result in a reduction in both the birth prevalence of NTD and the incidence of CHD, although not necessarily contemporaneously. If disordered homocysteine metabolism is the cause of both NTD and CHD, this has implications for future research and preventive strategies for these serious and often lethal diseases.

Coronary Disease↗
PubMed1999

Risk factors and 20-year stroke mortality in men and women in the Renfrew/Paisley study in Scotland.

BACKGROUND AND PURPOSE: The aim of this study was to relate risk factors in middle-aged men and women to stroke mortality over a long follow-up period. METHODS: In the early to mid 1970s, 7052 men and 8354 women from the Renfrew/Paisley prospective cohort study in Scotland were screened when aged 45 to 64 years. Risk factors measured included blood pressure, blood cholesterol and glucose, respiratory function, cardiothoracic ratio, smoking habit, height, body mass index, age, preexisting coronary heart disease, and diabetes. These were related to stroke mortality over 20 years of follow-up. RESULTS: Women's stroke mortality rates were similar to men's, unlike coronary heart disease mortality, in which case women's rates were lower than men's. Diastolic and systolic blood pressure, smoking, cardiothoracic ratio, preexisting coronary heart disease, and diabetes were positively related to stroke mortality for men and women, while adjusted forced expiratory volume in 1 second and height were negatively related. Cholesterol and body mass index were not related to stroke mortality. Glucose in nondiabetics was positively related to stroke mortality for women but not men, and there was evidence of a threshold effect at the highest levels of glucose. Former smokers had mortality rates that were similar to those of never-smokers. In sex-specific multivariate models, most variables retained a statistically significant association with stroke mortality, illustrating the multifactorial etiology of stroke. CONCLUSIONS: Overall, findings for women were similar to those for men. Control of risk factors for reduction of stroke mortality should be targeted at men and women in a similar fashion, particularly with reference to smoking cessation and blood pressure control.

Blood Glucose↗
PubMed1999

Postal urine specimens: are they a feasible method for genital chlamydial infection screening?

BACKGROUND: A United Kingdom (UK) screening programme for Chlamydia trachomatis has recently been announced. Pilot projects involving the opportunistic testing of women attending health facilities are due to commence in several sites. There is a danger that this approach will fail to obtain adequate population coverage. The alternative--true systematic population screening--is generally assumed to be unfeasible. Studies in Denmark using postal urine specimens have challenged this assumption. No such studies have been reported from the UK. AIM: To assess the potential of urine specimens sent by post as the basis for a UK population screening strategy for genital chlamydial infection. METHOD: Two hundred patients (100 men, 100 women) aged 18 to 45 years were randomly sampled from the list of one urban group practice. Subjects were mailed an explanatory letter, a urine sample container, a sexual lifestyle questionnaire, and a prepaid return envelope. Non-responders were contacted by telephone; persistent non-responders were visited at home. Samples were tested for Chlamydia by DNA amplification and enzyme immunoassay. RESULTS: Sixty-four (32%) subjects were no longer living at their GP registered address. Of the remaining 136, 126 (93%) responded to the survey and 113 (83%) accepted the request for a urine sample and completed a questionnaire. Acceptance rates were similar for men and women and across age groups. Four samples (3%) were Chlamydia positive. CONCLUSION: Home mailed urine specimen collection in conjunction with a self-completed postal questionnaire is feasible. This could provide a viable basis both for determining population Chlamydia prevalence and for a UK Chlamydia population screening strategy. Overall cost effectiveness of such a strategy will depend on the cost of the test used. Comparative performance characteristics of the different currently available tests in this setting have yet to be fully determined.

Adolescent↗
PubMed1998

Characterization of protein phosphatases in mouse oocytes.

Okadaic acid (OA) enhances the resumption of meiosis in mouse oocytes, indicating that serine/threonine protein phosphatase-1 (PP1) and/or PP2A is involved. However, specific identification of PP1 and/or PP2A in mouse oocytes has not been reported. Here we demonstrate that fully grown germinal vesicle-intact (GVI) mouse oocytes contain mRNA corresponding to two isotypes of PP1, PP1alpha and PP1gamma. In addition, the transcript for PP2A was also present. At the protein level only PP1alpha and PP2A were recognized in fully grown GVI oocytes by Western blot analysis. Neither of the PP1gamma spliced variant proteins, PP1gamma1 and PP1gamma2, was detectable. Immunohistochemical analysis of ovarian tissue from gonadotropin-stimulated adult mice resulted in subcellular localization of both PP1alpha and PP2A, but not PP1gamma, in oocytes from all stages of folliculogenesis. In primordial oocytes, PP1alpha and PP2A were present in the cytoplasm. In more advanced stages of oogenesis, PP1alpha, although still present in the cytoplasm, was highly concentrated in the nucleus, whereas PP2A was predominantly cytoplasmic with a distinct reduction in the nuclear area. Both PP1alpha and PP2A were immunodetectable in oocytes during the prepubertal period. Eleven-day-old mouse oocytes, considered OA-insensitive and germinal vesicle breakdown (GVB)-incompetent, displayed both PP1alpha and PP2A predominantly in the cytoplasm. By 15 days of age mouse oocytes, which are beginning to acquire OA sensitivity and GVB competence, showed a relocation of PP1alpha into the nucleoplasm while PP2A remained predominantly cytoplasmic. This is the first specific identification of PP1alpha and PP2A in mouse oocytes. The differential localization of PP1alpha and PP2A, in addition to the relocation of PP1alpha during the acquisition of meiotic competence, suggests that these PPs have distinct regulatory roles during the resumption of meiosis.

Animals↗
PubMed1998

Differing haemodynamic and catecholamine responses to exercise in three groups with peripheralautonomic dysfunction: insulin-dependent diabetes mellitus, familial amyloid polyneuropathy and pure autonomic failure.

The haemodynamic and catecholamine responses to supine exercise, and the effect on standing blood pressure (BP), were studied in three groups with peripheral autonomic dysfunction; insulin-dependent diabetes mellitus (IDDM), familial amyloid polyneuropathy (FAP) and pure autonomic failure (PAF). Healthy normal subjects were studied as controls. With exercise, BP increased in controls, was unchanged in IDDM and FAP, and fell in PAF. Heart rate (HR) increased more in controls than IDDM, FAP or PAF. Cardiac index (CI) increased less in IDDM than controls, FAP or PAF. Systemic vascular resistance (SVR) fell similarly in controls and IDDM, with a greater fall in FAP and PAF. Plasma noradrenaline increased in controls and IDDM only; plasma adrenaline did not change and plasma dopamine was undetectable in all groups. On standing, BP was unchanged in controls; BP fell pre- and post-exercise in IDDM, FAP and PAF, with a significantly greater fall post-exercise in FAP and PAF. In conclusion, the haemodynamic responses to supine exercise and to standing after exercise differed in the three groups with peripheral autonomic dysfunction. These differences, and also the similarities, between different forms of peripheral autonomic dysfunction, may be of relevance to the clinical assessment and therapy of these patients.

Adult↗