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Biomedical subjects

A Semmence

Publications and source records attributed to A Semmence.

At least 19 recordsLinked to original sources
PubMed1995

The tar reduction study: randomised trial of the effect of cigarette tar yield reduction on compensatory smoking.

BACKGROUND: Observational and short term intervention studies have reported that smokers of low tar cigarettes inhale more deeply (that is, compensate) than those who smoke high tar cigarettes. To quantify this effect a long term randomised trial was conducted on the effects of switching to low tar cigarettes. METHODS: The trial was carried out between April 1985 and March 1988 among cigarette smokers in the British Civil Service, measuring blood carboxyhaemoglobin (COHb) levels and serum cotinine levels as markers of tobacco smoke intake. Volunteers first switched to a cigarette brand yielding around 10% less tar than their usual brand to identify smokers able to change brand. The 434 subjects who successfully switched were then randomly allocated to one of three groups: (a) "fast reduction" group which changed to a brand of cigarettes with a tar yield of about half that of their usual brand; (b) "slow reduction" group which reduced to the same level in steps over several months; and (c) a control group which continued smoking cigarettes with a tar yield 10% lower than their usual brand. RESULTS: Over the course of the trial cigarette consumption declined slightly in all three groups. In both the "fast reduction" and the "slow reduction" groups, intake of COHb and cotinine was reduced, though not to the same extent as the yield reduction. Comparison of the results before randomisation with those at the end of the trial showed that a reduction in carbon monoxide yield of 45% was associated with a decrease in carbon monoxide intake of 19% (95% confidence interval 14% to 24%) and that a reduction in nicotine yield of 40% was associated with an 11% (6% to 16%) reduction in nicotine intake, reflecting relative intakes of about 1.5 for both carbon monoxide and nicotine in the "fast reduction" group. Results were similar in the "slow reduction" group with a 42% reduction in carbon monoxide yield, a 16% (11% to 22%) reduction in carbon monoxide intake, a 37% reduction in nicotine yield, and a 6% (0% to 13%) reduction in nicotine intake. Estimates of compensation derived from these results were 65% for carbon monoxide, 79% for nicotine, and 62% for tar. CONCLUSIONS: Compensation, demonstrated when switching from a high tar cigarette to a low tar one, was incomplete. Advising people who have failed to give up smoking to switch to low tar cigarettes will reduce the intake of smoke constituents to a small extent. This would be expected to decrease their risk of smoking-related diseases, although by a smaller amount than would be achieved by giving up smoking altogether.

Adaptation, Psychological↗
PubMed1994

The assessment of biological age: a report from the Department of Environment Study.

Indicators of ageing were measured in 397 male and 130 female London Civil Servants aged from 37 to 58 years of age. Grey hair, skin inelasticity, and arcus senilis were strongly and independently related to chronological age. Also independently related were serum albumin (negatively related in both sexes), baldness, serum creatinine, systolic blood pressure, serum calcium (negatively) and ESR in men, and serum cholesterol in women. Chronological age was regressed on the above variables for men and women separately to provide regression equations. Biological age for an individual was calculated by entering his or her results and calculating the residuals. Biological age in those who stopped smoking tended to be younger than chronological age by an average of 12-13 months in men and 1-4 months in women. Men and women who had never smoked had higher biological than actual ages but not after adjusting for regression dilution bias. Men who currently smoked had higher biological ages of 2-3 months but not women smokers (4-6 months lower). Similarly, men of lower employment grades had an average biological age 13 months older and women 8 months, compared with higher employment grades. These differences between employment grade appeared to be due to ESR, arcus senilis, systolic blood pressure and serum cholesterol. These four measurements may be markers of biological rather than chronological age, and the value of attempting to measure biological age is discussed.

Adult↗
PubMed1994

Age differences in biochemical and hematological measures during middle age.

Biochemical and hematological measures possibly associated with ageing were measured on a single occasion in 3402 male and 2152 female London Civil Servants aged from 35 to 59 years of age. These included erythrocyte sedimentation rate (ESR), blood hemoglobin and serum albumin, calcium, bilirubin, creatinine, urea, urate, high density lipoprotein (HDL), and total cholesterol. Independently and positively related to age were ESR with an estimated 47% 'increase' in men over the 15 years between ages 40 to 55 and a 40% increase in women; serum urea had a 6%/15-year increase in men and 20% in women; total cholesterol had a 6%/15-year increase in men and 18% in women; serum creatinine 'increased' by 2%/15-years in men and 5% in women. In women, urate, HDL cholesterol and hemoglobin increased with age group. Negatively related to age was serum bilirubin in both sexes (8% and 6% 'fall'/15-years in men and women respectively). Serum albumin and calcium fell with age group in men. The sexes differed in their relationship to aging for total cholesterol and HDL cholesterol (greater increase in women), serum calcium (small decrease in men and small increase in women), urate and hemoglobin (increases in women but not men). Urea increased more in women than men, and albumin decreased more in men than women (p < 0.001 for all comparisons with the exception of HDL cholesterol, p < 0.01). Changes during the menopause were thought to explain some of these findings.

Adult↗
PubMed1993

Smoking and blood pressure in the leg.

OBJECTIVES: To determine whether the calf:brachial ratio for systolic blood pressure is reduced in both current and ex-smokers of cigarettes. DESIGN: Cross-sectional study of the calf:brachial systolic blood pressure ratio and smoking history. SUBJECTS: Four hundred and ten male and 138 female civil servants aged 35-59 years working in the Department of the Environment Building, London. RESULTS: In men the systolic blood pressure ratio (Doppler calf:auscultatory brachial) decreased above the age of 50 years. However, different patterns were observed in those who had smoked at some time and those who had never smoked. In those who had never smoked the ratio in men aged 35-44 years was lower than that in men aged 55-59 years. In those who had smoked the average ratio rose from the age of 35-44 years to the age of 45-49 years and then fell to below the former value at the age of 55-59 years. There was a significant difference between lifelong non-smokers and current smokers at age 55-59 years. The pattern was similar in both male ex- and current smokers, and ex-smokers had results intermediate between those for current smokers and those who had never smoked. In women who had never smoked the ratio increased from the age of 35-44 years to the age of 50-59 years. In women aged 50-59 who currently smoke or used to smoke cigarettes the average ratio was close to that for women aged 35-44 years who had never smoked. CONCLUSIONS: The calf:brachial systolic blood pressure ratio is a simple measurement that may prove useful in detecting the early adverse effects of smoking on peripheral vascular disease. Lower ratios at older ages occurred in both current and ex-smokers, and the effects of smoking on peripheral arterial disease may not be easily reversible at older ages.

Adult↗
PubMed1991

The assessment of the relationship between blood pressure and sodium intake using whole-day, daytime and overnight urine collections.

The usefulness of whole-day, daytime (waking to retiring time) and overnight urine samples for assessing the relationship between blood pressure and sodium intake was examined in 301 male London civil servants, aged from 37 to 58 years old. Systolic blood pressure (SBP)/diastolic blood pressure (DBP) averaged 126/78 mmHg and the 24-h urinary excretion of sodium and potassium was 174 and 73 mmol, respectively. There was poor consistency between day- and night-time urine samples with respect to both sodium and potassium content. The urinary excretion of sodium and potassium was lower (P less than 0.001) in overnight than in daytime samples. After standardization for creatinine, the night: day ratio was 0.79 for sodium output and 0.55 for potassium excretion. Blood pressure, adjusted for age and body mass index, was significantly and positively correlated with overnight sodium excretion (SBP/DBP: slope = 0.061/0.046 mmHg/mmol) whereas the correlations with sodium excretion in daytime (0.010/0.004 mmHg/mmol) and whole-day (0.024/0.016 mmHg/mmol) urine samples were not significant. Blood pressure was significantly correlated with the sodium:potassium ratio in whole-day urine (1.941/1.968 mmHg/unit). As the agreement between daytime and overnight urine samples was low with respect to both sodium and potassium content, and due to the fact that the relationship between blood pressure and sodium in overnight samples may at least partially reflect pressure diuresis, overnight urinary sodium, even if related to sodium intake, cannot be employed to assess the association between salt in the diet and blood pressure.

Adult↗
PubMed1990

Blood cadmium in London civil servants.

Blood cadmium was measured in 466 randomly selected London civil servants not exposed to heavy metals at work. Blood cadmium ranged from 3.6 to 75.6 nmol/L (0.4 to 8.5 micrograms/L) with a geometric mean of 6.4 nmol/L (0.7 micrograms/L) in nonsmokers and 13.6 nmol/L (1.5 micrograms/L) in smokers (p less than 0.001). Blood cadmium was higher in women than in men (9.5 versus 7.8 nmol/L) and was inversely correlated with employment grade (p less than 0.001). The associations with age, body weight and alcohol intake were not significant. After adjusting for gender and the number of cigarettes smoked per day, 36% of the variance of blood cadmium was explained, while the contribution of employment grade was not significant. There was an unexpected negative relationship between serum creatinine and blood cadmium in men (r = -0.16; p less than 0.01). This was not true in women (r = +0.03), but the correlation remained present in men after adjustment for age, body mass index and smoking. In contrast, in the two sexes, the correlations between blood pressure and blood cadmium were weak and not statistically significant. In conclusion, in unexposed subjects, gender and smoking are important determinants of blood cadmium. In addition, a low level of environmental exposure to cadmium is not associated with a deterioration of renal function or an increase in blood pressure.

Age Factors↗
PubMed1990

Blood lead concentration, renal function, and blood pressure in London civil servants.

Blood lead concentration was measured in 398 male and 133 female London civil servants not subject to industrial exposure to heavy metals. The relation between blood lead and serum creatinine concentrations and blood pressure were examined. Blood lead concentration ranged from 0.20 to 1.70 mumol/l with a geometric mean concentrations of 0.58 mumol/l in men and 0.46 mumol/l in women (p less than 0.001). In women blood lead concentration increased with age (r = +0.27; p = 0.002). In the two sexes blood lead concentration was positively correlated with the number of cigarettes smoked a day (men r = +0.17 and women r = +0.22; p less than or equal to 0.01), with the reported number of alcoholic beverages consumed a day (men r = +0.34 and women r = 0.23; p less than 0.01), and with serum gamma-glutamyltranspeptidase (men r = +0.23 and women r = +0.14; for men p less than 0.01). Blood lead concentration was not correlated with body weight, body mass index, and employment grade. In men 14% of the variance of blood lead concentration was explained by the significant and independent contributions of smoking and alcohol intake and in women 16% by age, smoking, and alcohol consumption. In men serum creatinine concentration tended to rise by 0.6 mumol/l (95% confidence interval from -0.2 to +1.36 mumol/l) for each 25% increment in blood lead concentration. In men and women the correlations between blood lead concentration and systolic and diastolic blood did not approach statistical significance. In conclusion, in subjects not exposed to heavy metals at work gender, age, smoking, and alcohol intake are determinants of blood lead concentration. At a low level of exposure, lead accumulation may slightly impair renal function, whereas blood pressure does not seem to be importantly influenced. Alternatively, a slight impairment of renal function may give rise to an increase in blood lead concentration.

Alcohol Drinking↗
PubMed1987

The contribution of a moderate intake of alcohol to the presence of hypertension.

The relationship between blood pressure and alcohol intake was examined in 2434 male and 1608 female London civil servants. These subjects had been selected from 24,000 office workers on the basis of responses to a health questionnaire. The men had an average blood pressure of 134/80 mmHg and consumed a mean of 62 g alcohol/week as beer, 28 g/week as wine or fortified wine and 18 g/week as spirits (a total of 11.8 drinks/week). The women had an average blood pressure of 133/79 mmHg and consumed 7 g alcohol/week as beer, 25 g/week as wine and 11 g/week as spirits (a total of 4.4 drinks/week). Twenty-five per cent of men and 24% of women had a casual diastolic pressure equal to or greater than 90 mmHg and were considered to have diastolic hypertension on the one occasion. There was no increase in either systolic or diastolic pressure in men until total alcohol intake exceeded 50 drinks/week. However, 1% of all men had hypertension associated with drinking alcohol and in those with hypertension, alcohol may have been the cause in between 4 and 9%. Defining 'hypertension' as a diastolic blood pressure of 90 mmHg or above on one occasion, 12-14% of people drinking more than 50 drinks of alcohol per week had hypertension associated with this intake of alcohol, and similarly, of those with both 'hypertension' and this level of intake, 36% could attribute their high blood pressure to their alcohol consumption.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

The relationship between both sodium and potassium intake and blood pressure in London Civil Servants. A report from the Whitehall Department of Environment Study.

The relationship was examined in 459 male London Civil Servants between the casual lying systolic and diastolic (phase V) blood pressures measured in the clinic, and 24-hr urinary sodium and potassium excretion collected an average of 6 weeks later. Systolic and diastolic pressures, after adjusting for age and weight, were both negatively associated with the 24 hr potassium excretion (r = -0.17 [p less than 0.001, 95% confidence limits -0.07, -0.27) and r = -0.11 (p less than 0.05, 95% CL 0.00, -0.21) for systolic and diastolic pressure respectively]. Adjusted systolic but not diastolic pressure was also negatively associated with plasma potassium estimated at the time of blood pressure measurement (r = -0.15, p less than 0.001, 95% CL -0.06, -0.24). In 159 female London Civil Servants both systolic and diastolic pressures were negatively correlated with plasma potassium. However, there was no evidence for a negative relationship between urinary potassium excretion and blood pressure in women. Urinary sodium excretion was not related to blood pressure either in men or women. Blood pressure was also measured by the subjects at home over a one week period during which time the urine collection was made. There was no evidence for an association between blood pressure measured at home 6 weeks after the time of drawing blood, and plasma sodium. On the other hand, in men, the negative relationship between blood pressure and urinary potassium excretion was consistent and independent of the time and place of measuring blood pressure. This is consistent with a true effect of diet, a low potassium intake being associated with an increased blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Fibrinogen: a possible link between social class and coronary heart disease.

Mortality from coronary heart disease in civil servants in the lowest grade of employment has been found to be about three times that of men in the highest grade of employment. As part of an investigation of this finding several haemostatic variables were measured in a sample of 29 men in lower grades of employment and 45 men in higher grades. There was a significant difference in plasma fibrinogen concentrations between men in lower grades of employment and those in higher grades (mean 3.39 g/l v 2.95 g/l, respectively; p less than 0.01) but not in other haemostatic variables. Multiple regression analyses showed significant independent associations of fibrinogen concentration with smoking (p less than 0.05) and grade of employment (p less than 0.05). The size of the observed difference between the grades of employment was similar to that between those dying of coronary heart disease or surviving during longitudinal study; it may therefore be an important part of the mechanism underlying social class differences in coronary heart disease. The statistical relation between fibrinogen concentrations and other characteristics that may be concerned in the aetiology of coronary heart disease was examined. A summary measure of job stress was significantly related to fibrinogen concentration (p less than 0.01) and made a substantial contribution to explaining the differences between grades of employment. Behaviour type and a score of physical activity were not significantly related to fibrinogen concentration.

Adult↗
PubMed1982

A randomised controlled trial of the effects of screening for ulcer-type dyspepsia.

One hundred and ninety-nine male London office workers with dyspeptic symptoms elicited by a self-administered questionnaire were randomly allocated to intervention and control groups to assess the potential benefits of screening. The members of the intervention group were interviewed and examined, and those men who were considered to have a possible or probable peptic ulcer received a barium meal examination (53%). At the clinical interview the intervention group were advised against both smoking and drinking alcohol. Eighteen months later both groups were recalled for interview and examination and their sickness absence in the intervening period was assessed. The intervention group did not alter their cigarette consumption but did reduce their alcohol intake by an average of 10%. The control group increased their alcohol intake by 20%. Both groups tended to improve symptomatically, and there were no differences in symptoms between the groups at the end of the study. Sickness absence was not affected by the intervention. It is concluded that screening for ulcer-type dyspepsia is not justifiable in male London office workers.

Adult↗
PubMed1981

Blood pressure and plasma sodium and potassium.

1. Two thousand, three hundred and twenty-eight men and 1496 women between the ages of 35 and 64 years were screened for hypertension and their plasma sodium and potassium concentrations measured. Those on antihypertensive or diuretic treatment were excluded from further analysis. 2. After adjusting for age, body mass index and other variables, plasma potassium was negatively associated with both systolic and diastolic pressure in men and women. A decrease in plasma potassium of 1 mmol/l was associated with an increase in systolic pressure in women of 7 mmHg (P less than 0.001) and diastolic pressure of 4 mmHg (P less than 0.001). In men the corresponding increases were 4 mmHg (P less than 0.01) and 2 mmHg (P less than 0.05). 3. After adjusting for the other variables as above, plasma sodium was positively related to systolic blood pressure but not to diastolic pressure. An increase in plasma sodium of 1 mmol/l was associated with an increase in systolic pressure of 1 mmHg in both men (P less than 0.01) and women (P less than 0.05).

Adult↗
PubMed1980

Hernia repair and time off work in Oxford.

The variation in time off work was investigated in 261 men aged between 18 and 65 years whose inguinal herniae were repaired in Oxford hospitals in 1971/72 and 1974/75. The average time off was 51 calendar days compared with 70 days nationally. Complications, a heavy job, low sick pay, and family worries were found to be the main factors associated with increased time off, although they accounted for only 42 per cent of the variance. Men stopping smoking at the surgeon's request had less time off, and so had men who had been given an estimate before their operation of their likely duration of absence, especially when the estimate was given by the surgeon.

Absenteeism↗