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Biomedical subjects

B M Margetts

Publications and source records attributed to B M Margetts.

At least 19 recordsLinked to original sources
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↗
PubMed1991

The relation of maternal weight to the blood pressures of Gambian children.

The objective of the study was to relate blood pressure levels in children to their mother's weight in pregnancy. The blood pressures of 675 children aged from one to nine years in three villages in rural Gambia were measured. They were matched to antenatal clinic data which had been collected from all pregnant women in the three villages since 1980. Among children under eight years of age those born in the dry season had the highest blood pressures and were heavier. Their blood pressures were positively related to body weight and to mothers' weight at six months of pregnancy. These relationships were independent of mothers' age and parity, birthweight, gestational age, and placental weight. Among older children, aged eight and nine years, those born in the rainy season had the highest blood pressures. Their blood pressures were not related to their mothers' weight at six months of pregnancy. Rather they were inversely related to mothers' weight gain in the last trimester. An interpretation of these findings is that among young children differences in blood pressure are largely determined by rates of maturation. However, the long-term effects of adverse intra-uterine influences which elevate blood pressure become apparent in older children.

Age Factors↗
PubMed1991

Relationship between diet and smoking--is the diet of smokers different?

STUDY OBJECTIVE: The aim was to compare nutrient intakes of smokers, past smokers, and non-smokers. DESIGN: The study was cross sectional and compared nutrient intake by smoking status using data obtained from a concurrent study of diet. SETTING: The study took place in three towns in England: Ipswich, Wakefield, and Stoke on Trent. PARTICIPANTS: Food records were obtained from 1115 men and 1225 women aged 35 to 54 years, representing response rates of 84-86% in the three towns. MEASUREMENTS AND MAIN RESULTS: Diet was assessed using a 24h food record in household measures. For both men and women vitamin C, total fibre, beta carotene, and vitamin E intakes were lowest in the current smokers and highest in the non-smokers with past smokers having intermediate values. Polyunsaturated/saturated fat ratio was lowest in the current smokers. Men who smoked had higher energy intakes than those who did not. The lower fat intakes of beta carotene, vitamin C, fibre, and polyunsaturated fat in the smokers was due to fewer smokers eating a whole range of foods including fruit, wholemeal bread, cereals, and polyunsaturated margarine. Current smokers had a lower body mass index than non-smokers or past smokers despite their higher energy intakes. CONCLUSIONS: Smokers have different nutrient and food intakes compared with past smokers or non-smokers.

Body Mass Index↗
PubMed1991

Effect of socio-demographic conditions on growth of urban school children of Bangladesh.

The relationship between socio-demographic variables and growth of 242 school children from five schools in Dhaka city, Bangladesh, was investigated. The socio-demographic data were collected by questionnaire and the anthropometric data were collected by visits to each school on a prefixed date. Children from the high-family-income group showed significantly higher body weight, height, MUAC, SFT, wt/age, and ht/age compared with children from the low-family-income group. When the effect of age, sex, father's occupation and family size were adjusted for by means of multiple analysis of variance, the family income still showed a significant contribution to the variation in the anthropometric indices of these children. These findings suggest that family income makes a significant contribution as a determinant of growth of urban school children in Bangladesh.

Analysis of Variance↗
PubMed1990

Do stone formers have lower urinary fibrinolytic activity than controls?

A comparison of urinary fibrinolytic activity between 31 stone formers and 50 controls failed to demonstrate any significant difference and so failed to confirm an earlier independent observation. This may be due to methodological and design differences between the 2 studies, but does suggest reservations about the significance of lowered urinary fibrinolytic activity as a risk factor for renal stone disease. Dietary information from those taking part in the study suggests that a reduction of meat intake by stone formers might be associated with increased urinary fibrinolytic activity. This might account for the discrepancy between the 2 studies, in which case this observation could be of significance.

Creatinine↗