The natural history of eczema from birth to adult life: a cohort study.

BACKGROUND: Eczema is common in infancy; however, there is little evidence about its natural history to adulthood. OBJECTIVES: To study the natural history of eczema from birth to young adult life with particular reference to its relation to atopy. METHODS: A birth cohort of children with atopic family histories was followed for 23 years. Clinical examinations were conducted until the age of 7 years, skin-prick tests and serum total IgE were recorded in infancy and at ages 7 and 23 years, and questionnaires about eczema symptoms were completed at 15 and 23 years. RESULTS: Information was obtained on 497 subjects at birth, 482 at 1 year, 440 at 7 years, 363 at 15 years and 304 at 23 years. Eczema usually remitted from age 1 to 7 years but became more persistent from the age of 15 years, especially in those who were atopic. The prevalence of eczema rose in women from age 15 to 23 years but declined in men. Adults with eczema had higher IgE than those without at 3 months (geometric mean 3·0 vs. 1·7 kU L(-1); P=0·01), 7 years (107·9 vs. 45·2 kU L(-1); P=0·01) and 23 years (123·4 vs. 42·3 kU L(-1); P=0·01), and were more likely to have had positive skin-prick tests at 1 year of age. Current eczema was associated with raised IgE in infancy and adulthood but not in childhood. CONCLUSIONS: Predisposed infants and children with eczema usually grow out of the disease, but in adolescence it is more likely to persist. Adult eczema is related to atopy from the age of 3 months.

Optimization of dietary folate or low-dose folic acid supplements lower homocysteine but do not enhance endothelial function in healthy adults, irrespective of the methylenetetrahydrofolate reductase (C677T) genotype.

OBJECTIVES: We sought to study the effect of low-dose folic acid supplementation or optimization of dietary folate intake on plasma homocysteine and endothelial function in healthy adults. BACKGROUND: Elevated homocysteine is associated with cardiovascular disease, but it is not known whether this relationship is causal. Individuals homozygous (TT) for the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene ( approximately 12% of the population) have increased homocysteine levels, particularly in association with suboptimal folate intake. METHODS: Healthy subjects (n = 126; 42 of each MTHFR genotype) were included in this cross-over study of three interventions of four months each: 1) placebo plus natural diet; 2) daily 400-microg folic acid supplement plus natural diet; and 3) increased dietary folate intake to 400 microg/day. RESULTS: At baseline, homocysteine was inversely related to plasma folate and was higher in TT homozygotes. For the whole group, plasma folate increased by 46% after dietary folate and by 79% after supplementation, with reductions of homocysteine of 14% and 16%, respectively. Within the genotype, TT homozygotes exhibited the most marked changes in these variables. Brachial artery endothelial function, as determined by a change in end-diastolic diameter in response to increased flow, was not changed by increased folate intake (98 +/- 73 microm at baseline, 110 +/- 69 microm after a high-folate diet, 114 +/- 59 microm after supplementation and 118 +/- 68 microm after placebo). Plasma von Willebrand factor antigen was unaltered. CONCLUSIONS: Optimization of dietary folate or low-dose folic acid supplementation reduces plasma homocysteine but does not enhance endothelial function, irrespective of the MTHFR (C667T) genotype.

Lessons from the story of n-3 fatty acids.

The discovery of the effects of n-3 fatty acids came about as a result of contacts between scientists in different countries and disciplines who followed up some unexpected observations. There are probably other fields of research in which discoveries of similar importance await the application of lessons from this story.

Heart disease in British vegetarians.

A prospective study was conducted among customers of health food shops and members of societies interested in health foods. A total of 10,896 persons were followed for 10-12 y, including 4671 vegetarians and 6225 nonvegetarians. Mortality from ischemic heart disease (IHD) was significantly lower in the vegetarians than in the nonvegetarians; the difference was especially marked among the men. In a subset of 300 subjects, serum cholesterol and body mass index were lower in the vegetarians than in the nonvegetarians but there were no consistent differences in blood pressure between the two groups. Vegetarianism seems to confer some protection against IHD but it is not clear whether this is due to abstinence from meat or to a high consumption of vegetables.

Vegetarianism, dietary fiber, and mortality.

A prospective study was set up to test the hypotheses that the risk of death from various diseases is reduced by a high intake of dietary fiber or by vegetarianism. A simple screening questionnaire was distributed among persons with a special interest in health foods, and 10,943 subjects were recruited and followed-up. Their mortality was ascertained by flagging their National Health Service records, and analyzed after 7 yr. A significant negative association was found between vegetarianism and mortality from ischemic heart disease which was especially marked among the men and did not seem to be due to a confounding effect of smoking. No significant associations were found with fiber, although persons who habitually ate wholemeal bread had a lower mortality from cerebrovascular disease. These findings confirm other evidence of a lower mortality from heart disease among vegetarians.

The effect of fatty fish on plasma lipid and lipoprotein concentrations.

The effect of fatty fish consumption on plasma lipid and lipoprotein concentrations was studied in 118 healthy men in a cross-over controlled trial. Subjects ate 100 g or more of fatty fish at least twice a week for 3 months, and little or no fatty fish for another 3 months. The mean plasma triglyceride concentration decreased significantly by 6.7% on the fish diet; there were no significant changes in plasma total cholesterol, high-density lipoprotein cholesterol, or low-density lipoprotein cholesterol. A realistic intake of fatty fish has a detectable effect on blood lipids.

Mortality in vegetarians and nonvegetarians: detailed findings from a collaborative analysis of 5 prospective studies.

We combined data from 5 prospective studies to compare the death rates from common diseases of vegetarians with those of nonvegetarians with similar lifestyles. A summary of these results was reported previously; we report here more details of the findings. Data for 76172 men and women were available. Vegetarians were those who did not eat any meat or fish (n = 27808). Death rate ratios at ages 16-89 y were calculated by Poisson regression and all results were adjusted for age, sex, and smoking status. A random-effects model was used to calculate pooled estimates of effect for all studies combined. There were 8330 deaths after a mean of 10.6 y of follow-up. Mortality from ischemic heart disease was 24% lower in vegetarians than in nonvegetarians (death rate ratio: 0.76; 95% CI: 0.62, 0.94; P<0.01). The lower mortality from ischemic heart disease among vegetarians was greater at younger ages and was restricted to those who had followed their current diet for >5 y. Further categorization of diets showed that, in comparison with regular meat eaters, mortality from ischemic heart disease was 20% lower in occasional meat eaters, 34% lower in people who ate fish but not meat, 34% lower in lactoovovegetarians, and 26% lower in vegans. There were no significant differences between vegetarians and nonvegetarians in mortality from cerebrovascular disease, stomach cancer, colorectal cancer, lung cancer, breast cancer, prostate cancer, or all other causes combined.

Childhood asthma in four countries: a comparative survey.

BACKGROUND: Asthma mortality among young people varies widely between different countries. Geographical differences in asthma prevalence are also believed to exist, but evidence is sparse owing to the lack of multicentre surveys using common protocols. A survey was conducted of 12-year-old children living in defined areas of New Zealand, Wales, South Africa and Sweden, in order to see whether asthma prevalence and mortality rates in children show parallel differences. METHODS: Questionnaires enquiring about a history of asthma and respiratory symptoms were issued to the parent. The children performed a simple exercise challenge test. RESULTS: Information was obtained for 4353 children. A history of asthma at any time was reported for 16.8% of children in New Zealand, 12.0% in Wales, 11.5% in South Africa and 4.0% of Sweden, and a similar pattern was shown by several other indices of asthma (various relevant symptoms, inhaler use, response to exercise challenge, and asthma mortality at ages 5-19 years). In Sweden wheezing was negatively associated with pet ownership; elsewhere there was a positive (though non-significant) association. Cat ownership was highest in New Zealand and lowest in Sweden. CONCLUSIONS: The prevalence of asthma in children shows geographical variation which is parallel to that of asthma mortality, being high in New Zealand and low in Sweden. Differential exposure to animal allergens is a possible factor in this variation.

Why is chest disease so common in South Wales? Smoking, social class, and lung function: a survey of elderly men in two areas.

A respiratory survey was conducted in two British towns, one with a high mortality (Caerphilly) and one with a low mortality (Bath) from respiratory disease. A total of 513 men aged 65-74 years were seen. The Caerphilly men had poorer lung function than the Bath men; the overall difference in FEV1 and FVC for men aged 70 and 1.68m tall was 0.16 1 and 0.17 1 respectively. These differences appeared to be largely due to the greater tendency of the Caerphilly men to smoke and to an effect related to social class. Respiratory symptoms were also more common in Caerphilly, principally because of the effects of smoking and occupational group, although when these factors were allowed for there was still a significantly greater prevalence of breathless wheezing in Caerphilly.

Family size and paternal unemployment in relation to myocardial infarction.

Men who had been in hospital for myocardial infarction (MI) were compared with other male patients in an attempt to provide evidence on the hypothesis linking MI with poverty in childhood followed by relative affluence. In each of three social class groupings MI patients came from larger families than controls, and a higher proportion of their fathers had been unemployed for more than a year during their childhood. This gives some support to the hypothesis that childhood poverty may be associated with an excess risk of MI. There was no obvious evidence of a greater improvement in social class status among the MI patients compared with the controls.

Heart rate, employment status, and prevalent ischaemic heart disease confound relation between cereal fibre intake and blood pressure.

Cross sectional data from a survey of 2512 men aged 45-49 years were used to examine the confounding effects of heart rate, employment, and ischaemic heart disease (IHD) on the relation between cereal fibre intake and blood pressure. Daily cereal fibre intake (g/day) was associated with systolic pressure (r = -0.053, p less than 0.01), diastolic pressure (r = -0.057, p less than 0.01), and heart rate (r = -0.071, p less than 0.01). The associations were strengthened in employed men and inapparent in unemployed men. Unemployed men had more IHD than employed men. Persons with any manifestation of IHD had significantly higher blood pressure and heart rates but ate less cereal fibre (7.0 v 7.9 g/day, p less than 0.001) than those without IHD, regardless of employment status. In employed men, after adjustment for age, body mass index, prevalent IHD, and heart rate, systolic pressure changed -0.186 mmHg (95% CI = -0.362, -0.009) and diastolic pressure changed -0.111 mmHg (95% CI = 0.228, 0.005) for each gram of cereal fibre eaten daily. The association between cereal fibre and blood pressure was inapparent in unemployed men. Heart rate, employment, and prevalent IHD confound the association between cereal fibre intake and blood pressure. Future work concerning this relationship will have to account for the effects of these variables.

A randomised controlled trial to investigate the effect of a high fibre diet on blood pressure and plasma fibrinogen.

Two hundred and one subjects (147 men and 54 women) were randomly allocated to either a high cereal fibre diet or a low cereal fibre diet for four weeks. Each group then followed the alternative diet for a further four weeks. Cereal fibre intakes were 19g/d (31 g/d 21 g/d total fibre) and 6g/d (19g/d total fibre) on the high and low fibre diets respectively (p less than 0.001). Energy, protein, fat, carbohydrate, and alcohol intakes calculated from weighed intake records did not differ between the two diets, although there was a slight difference in body weight, the mean being 0.3 kg heavier at the end of the high fibre period. The high cereal fibre diet had no detectable effect on blood pressure or plasma fibrinogen.

Environmental factors and symptoms in infants at high risk of allergy.

STUDY OBJECTIVE: To identify environmental determinants of six symptoms associated with allergic disease in infancy. DESIGN: Infants were participants in a prospective randomised controlled trial of feeding practices in families with a history of atopy. SETTING: Infants were recruited in two maternity hospitals in S Wales and followed up in the community for 1 year. PARTICIPANTS: Mothers of 519 infants agreed to participate, but 36 were excluded (mainly for moving home or failing to attend for follow-up), leaving 483 in the study (253 male, 230 female). Infants were followed up and examined for evidence of allergic disease at 3, 6, and 12 months. MEASUREMENTS AND MAIN RESULTS: At each examination, mothers were questioned about episodes of illness in the infant, and the data presented relate to (reported and observed) eczema and nasal discharge, and (reported) wheeze, prolonged colds, diarrhoea and vomiting. Mothers kept a diary with details of feeding for the first 6 months. All homes were visited by a nurse who took samples of dust for dust mite antigen analysis. Extensive socio-demographic data were collected. None of the factors studied showed a convincing relationship with eczema. In a multiple logistic regression analysis breast feeding appeared to protect against wheeze, nasal discharge, colds, vomiting and diarrhoea. Having more siblings increased the likelihood of prolonged colds, and (together with overcrowding) of wheeze and nasal discharge. Maternal smoking and low social class were associated with wheeze, and house dust antigen with prolonged colds. Respiratory symptoms were associated with some aspects of housing but these could not be distinguished clearly from other social factors. Babies born in Autumn were at increased risk of wheeze, vomiting and diarrhoea. CONCLUSIONS: Environmental factors play an important part in determining risk of symptoms in potentially atopic babies. These factors are in principle open to manipulation.

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.

Social deprivation and asthma.

This study was conducted to see whether children living in socially deprived areas were more likely than other children to be admitted to hospital for asthma, and, if so, whether their excess risk was attributable to a higher prevalence of asthma or poorer treatment. Hospital admission rates for asthma were obtained for Cardiff electoral wards and compared with the Townsend indices of deprivation. A survey of respiratory symptoms was conducted in schoolchildren; prevalence of symptoms was compared with Townsend index and asthma admission rate for the schools' catchment areas. Asthma admissions were strongly correlated with Townsend indices at all ages. The prevalence of reported asthma and various degrees of wheeze in the schools was not significantly correlated with Townsend index or hospital admission rate in the corresponding areas. The presence of a smoker in the house was strongly associated with Townsend index and admission rate; children whose houses contained a smoker were more likely than others to have wheezed in the past year and to have disturbed nights due to wheezing. There was a non-significant negative association between Townsend index and regular use of inhaled steroids. The relationship between hospital admission for asthma and social deprivation is not explained by variations in prevalence, but it may be attributable to the aggravation of symptoms by active or passive smoking, and perhaps also to differences in management.

The long-term effect of dietary advice in men with coronary disease: follow-up of the Diet and Reinfarction trial (DART).

OBJECTIVE: To assess the long-term effect of dietary advice on diet and mortality after a randomised trial of men with a recent history of myocardial infarction. DESIGN: Questionnaire survey and mortality follow-up after a trial of dietary advice. SETTING: Twenty-one hospitals in south Wales and south-west England. SUBJECTS: Former participants in the Diet and Reinfarction Trial. MAIN OUTCOME MEASURES: Current fish intake and cereal fibre intake. All-cause mortality, stroke mortality and coronary mortality. RESULTS: By February 2000, after 21147 person years of follow-up, 1083 (53%) of the men had died. Completed questionnaires were obtained from 879 (85%) of the 1030 men alive at the beginning of 1999. Relative increases in fish and fibre intake were still present at 10 y but were much smaller. The early reduction in all-cause mortality observed in those given fish advice (unadjusted hazard 0.70 (95% CI 0.54, 0.92)) was followed by an increased risk over the next 3 y (unadjusted hazard 1.31 (95% CI 1.01, 1.70). Fat and fibre advice had no clear effect on coronary or all-cause mortality. The risk of stroke death was increased in the fat advice group-the overall unadjusted hazard was 2.03 (95% CI 1.14, 3.63). CONCLUSIONS: In this follow-up of a trial of intensive dietary advice following myocardial infarction we did not observe any substantial long-term survival benefit. Further trials of fish and fibre advice are feasible and necessary to clarify the role of these foods in coronary disease.

Coffee, blood pressure and plasma lipids: a randomized controlled trial.

A randomized controlled trial was conducted to examine the effects of coffee (as commonly drunk in Britain) on blood pressure and plasma lipids in healthy subjects. Fifty-four subjects followed three regimens successively, the order being randomized according to a Latin square design: five or more cups of coffee daily for 4 weeks; five or more cups of decaffeinated coffee daily for 4 weeks but no ordinary coffee; no coffee for 4 weeks. Coffee appeared to cause a small rise (of 3 mm Hg) in recumbent systolic blood pressure; this effect was less than, and obscured by, changes induced by posture and mild stress. No consistent changes attributable to coffee were found in diastolic blood pressure or pulse rate. Small changes in the expected directions occurred in plasma high density lipoprotein (HDL) cholesterol and apolipoprotein AI (decrease), and in total cholesterol, non-HDL cholesterol and apolipoprotein B (increase), but none of these were statistically significant. The effect of coffee on risk of heart disease in Britain is probably small.

A comparison of the effect of advice to eat either '5-a-day' fruit and vegetables or folic acid-fortified foods on plasma folate and homocysteine.

OBJECTIVE: To assess and compare the effects of natural folate (100 micro g) with those of folic acid from fortified sources (100 micro g/day) on plasma folate and homocysteine. DESIGN: Randomized controlled trial (parallel groups). SETTING: Men and women living in South Wales, UK. SUBJECTS: A total of 135 healthy individuals recruited from the local workforce and blood donor sessions. All subjects possessed the 'wild-type' CC genotype for C677T polymorphism in methylenetetrahydrofolate reductase (MTHFR). INTERVENTIONS: Subjects underwent one of the following dietary interventions for 4 months: (1) fortified diet-usual diet plus 100 microg/day folic acid from fortified foods; (2) natural folate diet-usual diet plus 100 microg/day folate from natural sources; (3) control-usual diet. RESULTS: The fortified group increased reported intake of folic acid from fortified foods compared to other groups (P<0.001) achieving an extra 98 microg/day (95% CI 88-108). The natural folate group increased reported intake of natural source folates compared with the other two groups (P<0.001), but achieved a mean increase of only 50 microg/day (95% CI 34-66). Plasma folate increased (P<0.01) by a similar amount in both intervention groups compared to controls (fortified group 2.97, 95% CI 0.8-5.1; natural group 2.76, 95% CI 0.6-4.9. Plasma homocysteine, vitamins B(6) and B(12) were not significantly changed. CONCLUSIONS: Subjects achieved increases in folate intake using fortified foods more easily than by folate-rich foods, however both sources increased plasma folate by a similar amount. These levels of intake were insufficient to reduce homocysteine concentrations in MTHFR CC homozygotes, but may be more effective in other genotypes.

Lack of benefit of dietary advice to men with angina: results of a controlled trial.

OBJECTIVE: To see whether mortality among men with angina can be reduced by dietary advice. DESIGN: A randomized controlled factorial trial. SETTING: Male patients of general practitioners in south Wales. SUBJECTS: A total of 3114 men under 70 y of age with angina. INTERVENTIONS: Subjects were randomly allocated to four groups: (1) advised to eat two portions of oily fish each week, or to take three fish oil capsules daily; (2) advised to eat more fruit, vegetables and oats; (3) given both the above types of advice; and (4) given no specific dietary advice. Mortality was ascertained after 3-9 y. RESULTS: Compliance was better with the fish advice than with the fruit advice. All-cause mortality was not reduced by either form of advice, and no other effects were attributable to fruit advice. Risk of cardiac death was higher among subjects advised to take oily fish than among those not so advised; the adjusted hazard ratio was 1.26 (95% confidence interval 1.00, 1.58; P=0.047), and even greater for sudden cardiac death (1.54; 95% CI 1.06, 2.23; P=0.025). The excess risk was largely located among the subgroup given fish oil capsules. There was no evidence that it was due to interactions with medication. CONCLUSIONS: Advice to eat more fruit was poorly complied with and had no detectable effect on mortality. Men advised to eat oily fish, and particularly those supplied with fish oil capsules, had a higher risk of cardiac death. This result is unexplained; it may arise from risk compensation or some other effect on patients' or doctors' behaviour.

Effects on respiratory health of a reduction in air pollution from vehicle exhaust emissions.

AIMS: To determine whether residents of congested streets have a higher prevalence of respiratory symptoms than residents of nearby uncongested streets, and whether their respiratory health improves following a reduction in exposure to traffic related air pollutants. METHODS: An area was identified where certain streets were subject to air pollution from heavy road traffic, which was likely to improve following the construction of a by-pass. A respiratory survey was conducted among the residents, together with the residents of nearby uncongested streets, at baseline and again a year after the by-pass opened. Measurements were made of air pollutant concentrations in both areas on both occasions. RESULTS: Initial concentrations of PM10 and PM2.5 were substantially higher in the congested than in the uncongested streets. When the by-pass opened, the volume of heavy goods traffic fell by nearly 50%. PM10 decreased by 23% (8.0 microg/m3) in the congested streets and by 29% (3.4 microg/m3) in the uncongested streets, with similar proportionate falls in PM2.5. There were no clear or consistent differences between the residents of the two areas initially in terms of symptoms or peak flow variability. Repeat questionnaires were obtained from 165 and 283 subjects in the congested and uncongested areas respectively, and showed a tendency for most symptoms to improve in both areas. For chest symptoms, the improvement tended to be greater in the uncongested area, although the difference between the areas was not statistically significant. Rhinitis and rhinoconjunctivitis tended to improve to a greater extent in the congested streets; the difference between the areas was significant for the degree to which rhinitis interfered with daily activities. Peak flow variability tended to improve in the uncongested area. CONCLUSIONS: The by-pass reduced pollutant levels to a degree that probably alleviates rhinitis and rhinoconjunctivitis but has little effect on lower respiratory symptoms.