Biomedical subjects

D C Greenwood

Publications and source records attributed to D C Greenwood.

At least 19 recordsLinked to original sources

PubMed2006

Use of itemized Till receipts to adjust for correlated dietary measurement error.

Recent studies suggest that measurement error in food frequency questionnaires includes a person-specific component correlated with that of other self-reported dietary assessments. Use of biomarkers has been recommended to adequately calibrate dietary assessment tools for unbiased estimation of associations between diet and disease. Data on biomarkers of intake are often collected only in small subsamples, because collection of biomarker data can be expensive and inconvenient for participants. In this paper, the authors propose a novel approach using itemized household grocery till receipts to calibrate dietary assessment. Till receipts are not self-recorded and the data obtained from them are not subject to person-specific bias, but the data need to be supported by self-completed diaries for foods eaten away from home. Till receipts may also prove cheaper to collect in larger samples. The authors discuss the many methodological challenges of using household-level data and discuss how till receipts might be used in practice, with or without the use of biomarkers.

Biomarkers↗

PubMed2006

Assessment of diet in young children with an emphasis on fruit and vegetable intake: using CADET--Child and Diet Evaluation Tool.

OBJECTIVES: To develop a concise, simple tool for use by non-specialists to assess diet in children aged 3-7 years attending primary schools. DESIGN: A 24-hour food tick list covering all aspects of the diet and with a focus on fruit and vegetable consumption was developed. This was compared against a 24-hour semi-weighed food diary obtained for the same day as the tick list. SETTING: Six primary schools with a range of socio-economic and ethnic backgrounds from a large city in the north of England (Leeds). PARTICIPANTS: One hundred and eighty children returned completed packs of information; a response rate of 77% of those who were willing to take part, 48% of those approached. RESULTS: On average, 2.4 items of fruit including juice (2.1 items as 5-a-day count) were eaten and 1.6 items of vegetables (excluding potato). Twenty-seven per cent and 36% of boys and 23% and 24% of girls reported not eating any fruit or vegetables, respectively, on the recording day. Correlations comparing the diary and tick list were high for both foods (range r=0.44 to 0.89) and nutrients (range r=0.41 to 0.68). The level of misclassification was much less than would be expected by chance. Parent and teacher evaluation of the tick list was very positive. Parents felt the tick list was easy and quick to complete. CONCLUSION: The Child and Diet Evaluation Tool (CADET) tick list has been used successfully for rapid collection of food and nutrient information from children aged 3-7 years from diverse social and ethnic backgrounds. The tool has performed better than many food-frequency questionnaires in comparison to a food diary.

Child↗

PubMed2006

Structured patient education: the diabetes X-PERT Programme makes a difference.

AIMS: To develop a patient-centred, group-based self-management programme (X-PERT), based on theories of empowerment and discovery learning, and to assess the effectiveness of the programme on clinical, lifestyle and psychosocial outcomes. METHODS: Adults with Type 2 diabetes (n = 314), living in Burnley, Pendle or Rossendale, Lancashire, UK were randomized to either individual appointments (control group) (n = 157) or the X-PERT Programme (n = 157). X-PERT patients were invited to attend six 2-h group sessions of self-management education. Outcomes were assessed at baseline, 4 and 14 months. RESULTS: One hundred and forty-nine participants (95%) attended the X-PERT Programme, with 128 (82%) attending four or more sessions. By 14 months the X-PERT group compared with the control group showed significant improvements in the mean HbA1c (- 0.6% vs. + 0.1%, repeated measures anova, P < 0.001). The number needed to treat (NNT) for preventing diabetes medication increase was 4 [95% confidence interval (CI) 3, 7] and NNT for reducing diabetes medication was 7 (95% CI 5, 11). Statistically significant improvements were also shown in the X-PERT patients compared with the control patients for body weight, body mass index (BMI), waist circumference, total cholesterol, self-empowerment, diabetes knowledge, physical activity levels, foot care, fruit and vegetable intake, enjoyment of food and treatment satisfaction. CONCLUSIONS: Participation in the X-PERT Programme by adults with Type 2 diabetes was shown at 14 months to have led to improved glycaemic control, reduced total cholesterol level, body weight, BMI and waist circumference, reduced requirement for diabetes medication, increased consumption of fruit and vegetables, enjoyment of food, knowledge of diabetes, self-empowerment, self-management skills and treatment satisfaction.

Aged↗

PubMed2005

HFE genotype modifies the influence of heme iron intake on iron status.

BACKGROUND: Public health policy to prevent iron deficiency through food fortification or other measures may be disadvantageous to people with hereditary hemochromatosis. METHODS: From a cohort of U.K. women, 2531 women were typed for C282Y and H63D mutations in the hemochromatosis gene. These women completed food frequency questionnaires and provided blood for iron status. RESULTS: C282Y homozygotes (n=31) had serum ferritin concentrations 2.4 times higher (95% confidence interval=1.9-3.1) than wild types (n=1774), but heterozygotes (n=726) were not different from wild types. H63D genotype had no effect on its own. The effect of heme iron intake (from meat, fish, and poultry) was 2.0 times greater (1.2-3.2) on C282Y homozygotes than other groups. Nonheme iron had little effect. CONCLUSIONS: There may be scope for dietary intervention in women homozygous for the C282Y mutation. C282Y heterozygotes and H63D homozygotes and heterozygotes have similar serum ferritin concentrations to wild type and need not reduce their meat intake other than as part of a normal healthy diet.

Adult↗

PubMed2004

The UK Women's Cohort Study: comparison of vegetarians, fish-eaters and meat-eaters.

BACKGROUND: This paper describes the development of the UK Women's Cohort Study and presents cohort baseline characteristics. METHODS: In total, 35,372 women, aged 35-69 years at recruitment, were selected to ensure a wide range of dietary intakes. Diet was assessed by a 217-item food-frequency questionnaire (FFQ). Detailed lifestyle information was collected by postal questionnaire. Vegetarians, fish-eaters and meat-eaters were compared. RESULTS: The cohort women are mainly white, well-educated, middle-class and married with children. They are health-conscious with only 11% current smokers and 58% taking dietary supplements. Twenty-eight per cent of subjects self-report as being vegetarian and 1% as vegan. However, only 18% are defined as 'vegetarian' from the FFQ. Fat provides 32% of energy; vitamin and mineral intakes are high, with a broad range of intakes. Meat-eaters are older, with a higher body mass index (BMI) and the lowest intakes of carbohydrate, fibre, vitamin C, folate, iron and calcium. Other fish-eaters are similar to vegetarians. Vegetarians have the lowest intakes of protein, fat and saturated fat. Oily fish-eaters have the lowest BMI; are the least likely to smoke or use full-fat milk; and are the most likely to use dietary supplements and consume the most fruit and vegetables. Oily fish-eaters have the highest total energy intake and vegetarians the lowest. Semi-skimmed milk, bread, potatoes, wine, bananas and muesli are important contributors to energy for all groups. CONCLUSION: A large cohort of middle-aged women has been created encompassing a wide range of different eating patterns, including diets currently of interest to research into protection against cancer and coronary heart disease. Participants will be followed up to study the effects of different food and nutrient intakes on long-term health outcomes.

Adult↗

PubMed2004

Inter-brand differences in iron content of breakfast cereals and their impact on measurement of iron intake.

BACKGROUND/AIMS: Fortified breakfast cereals (FBCs) are an important source of iron in the UK diet. In order to quantify their contribution to iron nutrition, food composition data for these products must be accurate. The very large amount of products available, together with inter-brand differences in iron content mean that discrepancies between the iron content of many FBCs and values in standard food composition databases (FCD) exist. The variation in reported iron contents of FBCs was examined and the impact of this variation on measurement of iron intake using standard food composition tables was investigated. METHOD: Data on the reported iron content of 128 FBCs were collected. Completed food diaries from 291 participants of the UK Women's Cohort study were used in the analysis. Mean iron intake from a 4-day food diary was calculated using UK food tables' values for FBCs. This was repeated using values reported by the manufacturer for each brand of cereal. The two sets of results were then compared. RESULTS: There is wide variation in iron content of breakfast cereals available in the United Kingdom. Use of FCD values instead of brand-specific values under- or overestimates an individual's iron intake by as much as 28 or 22% respectively. These results suggest that use of FCD values for breakfast cereals is potentially a source of substantial error in measurement of individuals' iron intake. CONCLUSION: Dietitians need to be aware of inter-brand differences in iron content and formulate advice accordingly. Failure to collect brand-specific data for the iron content of FBCs could lead to measurement error in measuring iron intake in dietary studies.

Adult↗

PubMed2004

Rising obesity and expanding waistlines in schoolchildren: a cohort study.

A cohort of schoolchildren was followed up over 6 years from 1996 to 2001. In the final year, 315 of 500 targeted children were measured. Body mass index (BMI) increased substantially over time (p<0.001), indicating a further rise in obesity into the secondary school years. Two new indicators of obesity were also measured. Waist circumference scores rose as substantially as BMI (p<0.001), and may be of particular significance given the association between abdominal girth in adults and cardiovascular morbidity. International Obesity Task Force measures were found to be more stringent than previous criteria, with no significant change noted over the time period.

Adolescent↗

PubMed2003

Use of supermarket receipts to estimate energy and fat content of food purchased by lean and overweight families.

The aim of this study was to compare the energy and fat content of food purchased for home consumption by households comprising mainly overweight individuals (OH), with those comprising mainly lean individuals (LH). 214 supermarket shoppers and their household were recruited from a Tesco supermarket in Leeds (UK). Households collected supermarket receipts and completed a shopping diary for 28-days, and each member of the household completed a 4-day food record. OH purchased food higher in fat (38% total energy from fat) than LH, (34.9%: p=0.001) and they purchased more energy and fat per adult equivalent, per day than LH (10.05 MJ compared to 9.15 MJ: p=0.01 and 103 g compared to 86 g:p=0.001). Households were 15% more likely to be classified as OH for each additional MJ of energy purchased per person, per day, after adjusting for number of children, household size, age, sex and social class. It was concluded that food purchasing behaviour may be linked to the prevalence of obesity in households who shop at supermarkets.

Adult↗

PubMed2003

Comparison of plasma biomarkers with dietary assessment methods for fruit and vegetable intake.

OBJECTIVE: To assess the variability and validity of plasma-based biomarkers of antioxidant vitamin, and fruit and vegetable intake. SETTING: Leeds, Wakefield, Huddersfield and Bradford, England. SUBJECTS: A total of 54 free-living, nonsmoking women recruited from participants of the UK Women's Cohort Study (UKWCS). METHODS: Two fasting blood samples were taken at two time points, 18 months apart. A 4-day food diary was completed prior to the first blood sample and a 24-h recall was conducted at the time of the second blood collection. All blood samples were analysed for ascorbic acid and four carotenoids. Associations between antioxidant vitamin intake from all food sources and supplements, as well as fruit and vegetable intake, and plasma levels of the antioxidant vitamins were assessed. RESULTS: Using the 4-day diary, positive associations were found between micronutrient intake from all food sources and plasma concentrations of ascorbic acid (P<0.01) and beta-carotene (P<0.01). No associations were seen between plasma micronutrient levels and specifically fruit and vegetable intakes. In general, associations between plasma levels and intakes assessed by the 24-h recall were less marked than those based on the 4-day diary. CONCLUSIONS: Plasma ascorbic acid and beta-carotene are good indicators of previous vitamin C and beta-carotene intake, from all food sources. However, caution is required in extrapolating these results to include individual food groups, rich in these vitamins. The results imply that the practice of using plasma biomarkers simply as a proxy measure of dietary intake is not valid and emphasise that plasma biomarkers are not simply a reflection of dietary intake, but also of a number of physiological processes. Biomarkers in nutrition epidemiological studies are however useful to measure nutrient status at the tissue level.

Adult↗

PubMed2002

Long-term outcome after tibial shaft fracture: is malunion important?

BACKGROUND: Fractures of the shaft of the tibia often heal with some angulation. Although there is biomechanical evidence that such angulation alters load transmission through the joints of the lower limb, it is not clear whether it can eventually lead to osteoarthritis. METHODS: One hundred and sixty-four individuals who had sustained a tibial shaft fracture were assessed in a research clinic thirty to forty-three years after the injury. The subjects were evaluated with regard to self-reported lower limb joint pain, stiffness, and disability (assessed with the Western Ontario and McMaster Universities [WOMAC] osteoarthritis questionnaire); clinical signs of osteoarthritis; and radiographic evidence of osteophytes and joint-space narrowing in the knees, ankles, and subtalar joints. RESULTS: Twenty-two (15%) of the 151 subjects who reported no other knee injury reported at least moderate knee pain, and eight (6%) of the 145 subjects who reported no other ankle injury reported at least moderate ankle pain. Seventeen (13%) of the 135 subjects who reported no other knee or ankle injury reported at least moderate disability. The ipsilateral side demonstrated a higher prevalence than the contralateral side in terms of pain with passive ankle movement (nineteen versus nine subjects, p = 0.02), pain with passive subtalar movement (fifteen versus four subjects, p = 0.01), and radiographic signs of ankle joint space narrowing (twelve subjects versus one subject, p = 0.0055). Knee osteoarthritis was frequently bilateral. Forty-seven fractures (29%) healed with coronal angulation of > or = 5 degrees. Apart from an association between shortening of > or = 10 mm and self-reported knee pain (p = 0.016), there were no significant univariate associations between these malunions and the development of osteoarthritis. Seventeen (15%) of 114 eligible subjects had overall malalignment of the lower limb, defined as a hip-knee-ankle angle outside the normal range of 6.25 degrees of varus to 4.75 degrees of valgus. This malalignment was due to the fracture malunion in nine subjects and predated the fracture in eight. In limbs with varus or valgus malalignment, there was an excess of subtalar stiffness (p = 0.04) and a nonsignificant trend toward more frequent knee pain. In limbs with varus malalignment, there was a nonsignificant trend toward more frequent radiographic evidence of osteoarthritis in the medial compartment of the knee joint. Most of the subjects in whom osteoarthritis was observed had normal overall alignment of the lower limb. CONCLUSIONS: The thirty-year outcome after a tibial shaft fracture is usually good, although mild osteoarthritis is common. Fracture malunion is not the cause of the higher prevalence of symptomatic ankle and subtalar osteoarthritis on the side of the fracture. Although varus malalignment of the lower limb occurs occasionally and may cause osteoarthritis in the medial compartment of the knee, other factors are more important in causing osteoarthritis after a tibial shaft fracture.

Aged↗

PubMed2001

Use of cumulative mortality data in patients with acute myocardial infarction for early detection of variation in clinical practice: observational study.

OBJECTIVES: Use of cumulative mortality adjusted for case mix in patients with acute myocardial infarction for early detection of variation in clinical practice. DESIGN: Observational study. SETTING: 20 hospitals across the former Yorkshire region. PARTICIPANTS: All 2153 consecutive patients with confirmed acute myocardial infarction identified during three months. MAIN OUTCOME MEASURES: Variable life-adjusted displays showing cumulative differences between observed and expected mortality of patients; expected mortality calculated from risk model based on admission characteristics of age, heart rate, and systolic blood pressure. RESULTS: The performance of two individual hospitals over three months was examined as an example. One, the smallest district hospital in the region, had a series of 30 consecutive patients but had five more deaths than predicted. The variable life-adjusted display showed minimal variation from that predicted for the first 15 patients followed by a run of unexpectedly high mortality. The second example was the main tertiary referral centre for the region, which admitted 188 consecutive patients. The display showed a period of apparently poor performance followed by substantial improvement, where the plot rose steadily from a cumulative net lives saved of -4 to 7. These variations in patient outcome are unlikely to have been revealed during conventional audit practice. CONCLUSIONS: Variable life-adjusted display has been integrated into surgical care as a graphical display of risk-adjusted survival for individual surgeons or centres. In combination with a simple risk model, it may have a role in monitoring performance and outcome in patients with acute myocardial infarction.

Age Factors↗

PubMed2001

The design features and practicalities of conducting a pragmatic cluster randomized trial of obesity management in primary care.

The aim of this paper is to describe the design features and practicalities of conducting a cluster randomized trial of obesity management in primary care. The aim of the trial is to assess the effectiveness of an obesity management educational intervention delivered to staff within primary care practices (unit of randomization) in terms of change in body weight of their patients (unit of analysis) at one year. The design features which merit particular attention in this cluster randomized trial include standardization of intervention, sample size considerations, recruitment of patients prior to randomization of practices, method of randomization to balance control and intervention practices with respect to practice and patient level characteristics, and blinding of outcome assessment. The practical problems (and our solutions) associated with implementing these design features, particularly those that result in a time delay between baseline data collection, randomization and intervention, are discussed.

Adolescent↗

PubMed2001

The use of supermarket till receipts to determine the fat and energy intake in a UK population.

OBJECTIVES: To validate the use of supermarket receipts as an index of fat and energy intake in a population that buys most of its food from supermarkets. DESIGN: Cross-sectional, prospective dietary survey - feasibility study. SETTING: Households situated within a 20-mile radius of a large (Tesco) supermarket in Leeds. SUBJECTS: Two hundred and fourteen households who spend >or=60% of their food purse in (Tesco and other) supermarkets. RESULTS: Mean daily household purchase of fat, energy and percentage energy from fat contained in food from supermarkets were 185 g, 19.2 MJ and 35.9%. Mean daily household intakes of fat and energy were 190 g and 20.7 MJ, and 35% of energy was derived from fat. Mean household size was 2.4 persons. The association between the amount of fat and energy purchased from supermarkets and the amount of fat and energy consumed by households was strong. 0.90 MJ (95% confidence interval (CI): 0.8-1.0) of energy were consumed for every 1 MJ purchased from supermarkets and 0.76 g (95% CI: 0.64-0.87) of fat were consumed for every 1 g of fat purchased. CONCLUSIONS: The results show a strong association between estimates of the intakes of fat and energy and percentage energy from fat using 4-day food diaries and 28 days of receipts, in populations who buy most of their food from supermarkets. They also show that the fat content of total food purchases from supermarkets is 35.9% energy from fat compared with 33% energy from fat recommended by the Department of Health. This preliminary research indicates the feasibility of and potential for utilising large quantities of readily available data generated from supermarket checkouts in dietary surveys.

Adolescent↗

PubMed2001

A randomized controlled trial to investigate brackets bonded with a hydrophilic primer.

OBJECTIVE: To compare the clinical failure rates of brackets bonded using a prototype hydrophilic primer, designed to be insensitive to moisture, with brackets bonded with a conventional primer. DESIGN: Single centre randomised controlled clinical study. Thirty-three patients were bonded using a split mouth technique: randomly allocating the hydrophilic primer to one side of the mouth and a conventional primer to the other. SETTING: Hospital orthodontic department, Bradford, UK. SUBJECTS: Orthodontic patients requiring fixed appliances. MAIN OUTCOME MEASURES: The site and time to bond failure was recorded for each bracket that failed over 6 months. RESULTS: Using survival analysis, there was an increased risk of bracket failure when bonded with the hydrophilic primer compared with the conventional primer (hazard ratio = 2.2, 95% confidence interval: 1.1 to 4.5, P = 0.01). CONCLUSIONS: This hydrophilic primer cannot be recommended for routine clinical use.

Adolescent↗

PubMed2001

A simple benchmark for evaluating quality of care of patients following acute myocardial infarction.

OBJECTIVE: To develop a simple risk model as a basis for evaluating care of patients admitted with acute myocardial infarction. METHODS: From coronary care registers, biochemistry records and hospital management systems, 2153 consecutive patients with confirmed acute myocardial infarction were identified. With 30 day all cause mortality as the end point, a multivariable logistic regression model of risk was constructed and validated in independent patient cohorts. The areas under receiver operating characteristic curves were calculated as an assessment of sensitivity and specificity. The model was reapplied to a number of commonly studied subgroups for further assessment of robustness. RESULTS: A three variable model was developed based on age, heart rate, and systolic blood pressure on admission. This produced an individual probability of death by 30 days (P(30)) where P(30) = 1/(1 + exp(-L(30))) and L(30) = -5.624 + (0.085 x age) + (0.014 x heart rate) - (0.022 x systolic blood pressure). The areas under the receiver operating characteristic curves for the reference and test cohorts were 0.79 (95% CI 0.76 to 0.82) and 0.76 (95% CI 0.72 to 0.79), respectively. To aid application of the model to routine clinical audit, a normogram relating observed mortality and sample size to the likelihood of a significant deviation from the expected 30 day mortality rate was constructed. CONCLUSIONS: This risk model is simple, reproducible, and permits quality of care of acute myocardial infarction patients to be reliably evaluated both within and between centres.

Adult↗

PubMed2001

Poor prognosis of patients presenting with symptomatic myocardial infarction but without chest pain.

OBJECTIVE: To describe the clinical features, prognosis, and treatment of patients presenting with atypical forms of acute myocardial infarction. DESIGN: Consecutive cases of possible acute myocardial infarction were sought from coronary care registers, biochemistry records, and hospital management systems. Case notes were reviewed and predefined epidemiological and clinical variables were abstracted. SETTING: 20 adjacent hospitals in the former Yorkshire region. PATIENTS: 3684 consecutive cases of possible acute myocardial infarction admitted in a three month period were identified, of whom 2096 had a first episode of confirmed acute myocardial infarction. RESULTS: 20.2% of all patients admitted with an eventual diagnosis of acute myocardial infarction presented with symptoms other than chest pain. Compared with the group presenting with chest pain, these patients were older (76.6 v 69.1 years, p < 0.001), were more often women (54.6% v 35.3%, p < 0.001), and were more likely to have a history of heart failure (18.6% v 6.9%, p < 0.001). They had a higher 30 and 365 day mortality (49.2% and 61.0%, respectively) compared with patients presenting with chest pain (17.9% and 26.2%). In a Cox regression analysis the hazard ratio for presentation without chest pain was 1.60 (95% confidence interval 1.30 to 1.97) (p < 0.001) adjusted for age, heart rate, blood pressure, left ventricular impairment, and infarction with ST segment elevation as covariates. Importantly, they were also less likely to receive treatments with a proven ability to improve prognosis. CONCLUSIONS: Atypical presentation of myocardial infarction without chest pain is common and associated with increased mortality. This may result in part from a failure to use beneficial treatment strategies.

Age Distribution↗

PubMed2000

Seven unique food consumption patterns identified among women in the UK Women's Cohort Study.

OBJECTIVE: [corrected] To identify groups of subjects with similar food consumption patterns so that complex disease-diet relationships can be investigated at the level of the whole diet, rather than just in terms of nutrient intake. SUBJECTS: 33,971 women in the UK Women's Cohort Study. 60,000 women on the World Cancer Research Fund mailing list were initially invited to take part. Subjects were selected to include a high proportion of vegetarians. DESIGN: The cohort completed a 217 item food frequency questionnaire. Cluster analysis was used to identify groups of women with similar food consumption patterns. Clusters were compared on socio-demographic characteristics, indicators of health and diet, and nutrient intakes. RESULTS: Seven clusters were identified including two vegetarian clusters. Groups appeared to be differentiated by differences in food types and in diversity of diet. Socio-demographic, health and diet characteristics and nutrient intakes all differed significantly between groups. CONCLUSION: Classifying diets in more pragmatic terms than just nutrient intake should provide valuable insight into understanding complex diet-disease relationships. Dietary advice, whilst based on nutrient content of meals, needs to take account of the combinations of different food types that people naturally choose to use together. SPONSORSHIP: World Cancer Research Fund.

Adult↗

PubMed2000

Investigation of a hydrophilic primer for orthodontic bonding: an in vitro study.

A common reason for bond failure is moisture contamination. This study investigates the in vitro bond strength of brackets bonded using a new hydrophilic primer, designed to be insensitive to moisture, and compares it with a conventional primer. Using a standardized technique, the in vitro bond strength of brackets bonded with the hydrophilic primer was compared to identical brackets bonded with a conventional primer. Although designed to be moisture insensitive, the directions for use stipulate drying the teeth before bonding. Therefore, for the purposes of comparison with a conventional primer the experiment was conducted under dry conditions. The results were analysed using the Weibull distribution modelling. The median bond strength with the hydrophilic primer (6.43 MPa, 95 per cent C.I. 7.69-9.50) was significantly lower (P = 0.0001) than the conventional primer (8.71 MPa, 95 per cent C.I. 5.89-7.59). The Weibull distribution modelling showed that brackets bonded with the hydrophilic primer were 3.96 times more at risk of failure (95 per cent C.I.: 2.39-6.56; P <0.0001). The bond strength at which 5 per cent of the brackets failed was also lower for the hydrophilic primer. The bond strengths obtained with the hydrophilic primer were significantly lower than with the conventional primer. Although the median bond strength values were promising, the laboratory results for this particular hydrophilic primer were disappointing when using the Weibull analysis, where the whole distribution of bond strength is taken into account.

Adolescent↗