Search PubMed⌕ Search

Biomedical subjects

B M Margetts

Publications and source records attributed to B M Margetts.

At least 37 records · Page 2Linked to original sources
PubMed1996

Does dietary intake of vitamins C and E influence lung function in older people?

Antioxidants in the lung have a protective role against oxidative damage. We have investigated whether dietary antioxidant intake in elderly people is related to lung function. Dietary intakes of ascorbic acid (vitamin C) and alpha-tocopherol (vitamin E) and lung function were assessed in 178 men and women aged 70 to 96 yr selected on the basis of reported respiratory symptoms. After adjustment for age, gender, height, smoking habits, total energy intake, and vitamin C intake by multiple linear regression, vitamin E intake was significantly associated with FEV1 p = 0.012 and FVC p = 0.003. There was no evidence of any interaction between vitamin E intake and current tobacco smoking as determinants of lung function. For every extra milligram increase in vitamin E in the daily diet, FEV1 increased by an estimated 42 ml and FVC by an estimated 54 ml. These results suggest that dietary intake of vitamin E may influence lung function in the elderly, but food frequency questionnaires in this study were not of sufficient sensitivity to explore this hypothesis further.

Aged↗
PubMed1996

The determinants of plasma beta-carotene: interaction between smoking and other lifestyle factors.

OBJECTIVE: To assess the effect of cigarette smoking on the relationship between dietary intake and circulating levels of beta-carotene. DESIGN: A secondary analysis of data collected for the Diet and Nutritional Survey of British Adults by The Department of Health and The Ministry of Agriculture, Fisheries and Food; the study was a cross-sectional survey of a representative sample of the British population. SETTING: The study was conducted on a free living adult (16-64 years of age) population resident in Great Britain. SUBJECTS: 1483 subjects completed a seven day weighed inventory and provided a blood sample. RESULTS: Smokers had statistically significantly lower dietary intakes and circulating levels of beta-carotene than non-smokers. At the same level of dietary intake, smokers were more likely to have lower circulating levels than non-smokers. For every 1000 micrograms change in dietary intake, there was a 0.01 mumol/l change in plasma beta-carotene in smokers and a 0.04 mumol/l change in non-smokers. The effect of smoking on circulating levels of beta-carotene persisted after adjusting for other factors. CONCLUSIONS: The results suggest that smoking places extra demands on the host; the higher risk of heart disease for smokers may be due to a combination of an increased inflammatory response, reduced host defences, and increased levels of circulating LDL. Failure to take account of the interaction between risk factors may distort the estimates of the relative importance of each factor when considered in isolation.

Adolescent↗
PubMed1996

Serum retinol and biochemical measures of iron status in adolescent schoolgirls in urban Bangladesh.

OBJECTIVE: To examine the relationship between serum retinol and biochemical indices of iron nutritional status amongst adolescent girls in urban Bangladesh. DESIGN: A cross-sectional study. SETTING: Girls' high schools in Dhaka City, Bangladesh. SUBJECTS: Adolescent girls, n = 225, aged between 12 and 15 years, from four urban schools participated in the study. Information on socio-economic conditions were obtained using a questionnaire. The height and weight of each girl were measured and a sample of blood was taken for biochemical analyses. RESULTS: Twenty-two per cent of the participants were found to be anaemic (Hb < 120 g/l), 15% had subnormal serum iron ( < 7.16 mumol/l) and about 25% were iron deficient judged by serum transferrin saturation (TS < 15%). Eleven per cent of the participants had low levels of serum retinol ( < 1.05 mumol/l). Anaemic girls (n = 51) were found to have significantly lower serum retinol as well as lower packed cell volume (PCV), mean corpuscular haemoglobin concentration (MCHC), serum iron, TS, and higher serum total iron binding capacity (TIBC) compared with those with normal haemoglobin levels. When the girls were classified by serum retinol, the third with the highest serum retinol had significantly higher levels of haemoglobin, PCV, MCHC and serum iron levels. When age, family size, family income, expenditure on food, education of the parents, supplementation with vitamin A or iron and menstruation at the time of study were accounted for by multiple regression analysis, a strong relationship was found for serum retinol concentration with PCV, MCHC, haemoglobin, serum iron and TS. For 1 mumol/l change in serum retinol concentration there was a 10.1 g/l change in haemoglobin whilst taking other factors into account. CONCLUSION: The data indicate that there is an interaction between serum retinol and biochemical indices of iron nutriture in adolescent girls who do not display any clinical signs of overt deficiency.

Adolescent↗
PubMed1995

Development of a scoring system to judge the scientific quality of information from case-control and cohort studies of nutrition and disease.

A scoring system was developed to help judge the scientific quality of observational epidemiologic studies linking diet with risk of cancer. The scoring system was developed from key headings used in developing research protocols and included questions under headings: three for case-control studies (dietary assessment, recruitment of subjects, and analysis) and four for cohort studies (dietary assessment, definition of cohort, ascertainment, and analysis). Points were awarded for questions in each section, and a total score was derived. Interobserver variation was assessed for five case-controls and five cohort studies for 13 observers: 1 observer repeated the assessment of each paper. Absolute scores and ranking within observer were assessed. There was good agreement between observers in the ranking of studies. Papers that scored higher presented sufficient detail to enable the questions in the scoring system to be answered more easily. For some studies, the information required was either not collected or, if it was collected, not presented. In either case, the frequent lack of information available to judge papers raises questions about the editorial policy and review process of journals publishing dietary studies as much as it does about the scoring system. Applying the scoring system to a review of meat and cancer risk suggested that, taking the score into account, from what seemed like a large literature, there were relatively few studies that scored well (defined as a score > 65%), but these studies tended to provide more consistent information.

Case-Control Studies↗
PubMed1994

Linking the field to the laboratory in nutrition research.

The three examples presented illustrate the dynamic way in which the field and the laboratory interact. Both types of study rely on sound research design and clear articulation of the relevant exposure. In all studies it is essential to consider the effect that measurement error will have on the estimate of the effect of the exposure on the outcome. Epidemiological studies rely on metabolic research to refine the methods and measures of nutritional exposures used in studies of cause-effect relationships. Metabolic studies rely on population studies to determine whether the experimental evidence they reveal is of public health importance. The Nutrition Society provides a vital forum within which this exchange between the field and the laboratory will continue.

Diet↗
PubMed1993

Interactions between people's diet and their smoking habits: the dietary and nutritional survey of British adults.

OBJECTIVE: To compare diet, nutrient intakes, and biochemical measures between smokers and non-smokers. DESIGN: Analysis of data collected in cross sectional survey conducted in 1986 and 1987. Subjects were recruited from electoral wards in England, Wales, and Scotland to reflect the regional distribution of the population. SUBJECTS: 2197 subjects (70% of those asked) aged between 16 and 64 undertook dietary assessment. Of these, 1842 subjects were considered to have kept a record typical of their usual dietary intake and had given data on smoking, and their results were analysed: 1224 non-smokers (631 men), 359 light smokers (166 men), and 259 heavy smokers (153 men). MAIN OUTCOME MEASURES: Differences in dietary, nutrient, and biochemical measures between nonsmokers and smokers. RESULTS: Smokers ate more white bread, sugar, cooked meat dishes, butter, and whole milk and less wholemeal bread, high fibre breakfast cereals, fruit, and carrots. Smokers had lower intakes of polyunsaturated fat, protein, carbohydrate, fibre, iron, carotene, and ascorbic acid. Adjusting for other covariates did not substantially alter the pattern of intakes. At the same dietary intake of carotenoids smokers were more likely to have lower circulating serum beta carotene concentrations than non-smokers. CONCLUSIONS: The diet and nutrient intakes and circulating levels of nutrients of smokers were different from those of non-smokers. Smokers were more likely to have an imbalance between the dietary intake of antioxidant nutrients and the metabolic demand for antioxidant protection. This imbalance is likely to make smokers more susceptible to oxidative damage. Smokers are at increased risk of chronic disease because their diets are different and because smoking creates an altered pattern of demand for specific nutrients. The diets of smokers not only fail to meet the unusual requirements for specific nutrients to satisfy the altered pattern of demand but are likely to exacerbate the damage caused by smoking.

Adult↗
PubMed1993

Interactions between growth and nutrient status in school-age children of urban Bangladesh.

The relationship between biochemical, anthropometric, and sociodemographic indexes was investigated in 242 children aged 5-12 y from five schools in Dhaka City, Bangladesh. As height-for-age increased so too did the mean serum concentrations of hemoglobin, protein, vitamin A, and zinc; serum copper concentrations were highest in the shortest group. Serum copper concentrations were highest in those with the lowest serum vitamin A concentrations. By multiple regression analysis, family income, age, weight-for-age, hemoglobin, and serum copper were strongly related to serum vitamin A. For every unit change in serum vitamin A there was a 4.92 unit change in hemoglobin, when all the other factors were taken into account. This study shows that there is a complex interaction between concentrations of biochemical indexes of nutritional status and other anthropometric, biochemical, and sociodemographic variables.

Aging↗
PubMed1993

Comparison of a food frequency questionnaire with a 10-day weighed record in cigarette smokers.

The aim of the study was to compare nutrient intakes estimated by a self-administered food frequency questionnaire and a 10-day weighed record in 122 men and 179 women cigarette smokers aged 40-59 years. Comparison of nutrient intake by means, per cent mean differences and ability to rank individuals correctly between the methods showed good agreement for most nutrients. Spearman rank correlations were statistically significant for all nutrients except vitamin A intake in men; adjusting for energy intake increased the strength of the associations found. Bland-Altman plots showed differences in agreement over the range of intakes for energy in men and ascorbic acid in women. Food frequency questionnaires may be used to assess the dietary habits of smokers, but some caution is required and the method should be assessed in the study sample before being applied to the whole sample.

Ascorbic Acid↗
PubMed1992

Effect of family size and income on the biochemical indices of urban school children of Bangladesh.

The relationship between family size and income and the biochemical indices of 242 children (aged from 5 to 12 years) from five schools in Dhaka City, Bangladesh, was investigated. Socio-economic data were collected by questionnaire and blood samples were drawn by visiting each school on a prefixed date. Mean levels of all measures, except for serum zinc, fell within the normal range. Older boys, but not girls (10-12 years of age) had statistically significantly higher haemoglobin, serum protein and serum vitamin A levels compared with those of the younger boys (5-9 years of age). The children were divided into three family size groups (small, up to 4 members; medium, 5-7 members; and large, 8 or more) to investigate the effect of family size on the biochemical data. The children from smaller families showed significantly higher levels of haemoglobin and serum vitamin A compared with the children from large families. For serum protein, copper and zinc, there was no statistically significant difference between the children of different family size groups. To analyse the effect of family income, children were divided into three income groups (low, up to taka 2000; medium, taka 2001-4500; and high, 4501 or more). The children from the low family income group had significantly lower serum protein (7.5 g/100 ml) and haemoglobin (13.4 g/100 ml) levels compared with those of the children from the high family income group (for protein, 7.7 g/100 ml and haemoglobin, 14.1 g/100 ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗