Biomedical subjects

K T Khaw

Publications and source records attributed to K T Khaw.

At least 19 recordsLinked to original sources

PubMed2006

Effects of physical activity on evolution of proximal femur structure in a younger elderly population.

INTRODUCTION: For a fixed weight, a wider bone of standardised length is stiffer. But moving the cortices away from the centre of mass risks creating structural (elastic) instability, and hip fractures have been postulated to occur as a consequence of buckling of the thinned supero-lateral femoral neck cortex during a fall. We hypothesised that stereotyped physical activity (e.g., walking) may help conserve bending resistance (section modulus, Z) through redistribution of bone tissue, but it might be at the expense of supero-lateral cortical stability. METHODS: Hip structural analysis (HSA) software applied to DXA scans was used to derive measurements of section modulus and distances of a cross-section's centre of mass from the supero-lateral cortical margin (lateral distance, in cm). DXA scans were obtained on 1361 men and women in the EPIC-Norfolk population-based prospective cohort study. Up to 4 repeat DXA scans were done in 8 years of follow-up. Weight, height and activities of daily living were assessed on each occasion. A detailed physical activity and lifestyle questionnaire was administered at baseline. The lateral distance was measured on three narrow cross-sections with good precision: narrow neck (NN, coefficient of variation 2.6%), intertrochanter (IT) and shaft (S). A linear mixed model was used to assess associations with predictors. RESULTS: Ageing was associated with medial shifting of the centre of mass, so that lateral distance increased. Both greater weight and height were associated with greater lateral distance (P<0.0001). Among physical activity-related variables, walking/cycling for >1 h/day (P=0.025), weekly time spent on moderate impact activity (P=0.003), forced expiratory volume in 1 s (NN and IT, P<0.026) and lifetime physical activity (IT, P<0.0001) were associated with higher lateral distance. However, after adjusting for these variables, activities of daily living scores (NN, P<0.0001) and weekly time spent on low impact hip flexing activities were associated with shorter lateral distance (P=0.001). Greater baseline lateral distance was significantly associated with increased risk of subsequent hip fracture (n=26) in females (P<0.05, all regions) independently of age, height and bone mineral content. CONCLUSION: The age-related shift medially of the centre of mass of the femoral neck and trochanter may have adverse effects on fracture resistance in the event of a fall, so compromising the beneficial effects of walking on fitness, strength and risk of falling. The role of more diverse physical activity patterns in old age that impose loading on the supero-lateral cortex of the femur, involving for example hip flexion and stretching, needs investigation for their ability to correct this medial shifting of the centre of mass.

Aged↗

PubMed2006

Tissue factor serum levels and the risk of future coronary artery disease in apparently healthy men and women: the EPIC-Norfolk prospective population study.

INTRODUCTION: Tissue factor (TF) has been implicated in coronary artery disease (CAD). High levels of circulating TF are found in patients with acute atherothrombotic events. Whether high serum TF levels predict risk of future CAD independent of known risk factors remains unknown. METHODS: We conducted a prospective case-control study nested in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk population study. Cases (n=1037) were apparently healthy men and women, aged 45-79 years, who developed fatal or non-fatal CAD during follow-up. Controls (n=2005) were matched by age, sex, and enrolment time. Serum TF levels were measured using high-affinity antibodies. RESULTS: In men, median TF levels were not significant higher in cases than in controls (59.0 pg mL-1, range: 16.7-370.4 vs. 54.9 pg mL-1, range: 16.2-452.4). In women, median TF levels were not significant higher in controls than in cases (73.4 pg mL-1, range: 16.7-492.3 vs. 50.5 pg mL-1, range: 16.5-376.7). The incidence of smoking was about double in the lowest compared with the highest TF quartile. Correcting for sex, age, body mass index, smoking, diabetes, systolic blood pressure, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol and C-reactive protein levels, the risk of future CAD was 1.05 (95% CI: 0.81-1.36) for people in the highest TF quartile, compared with those in the lowest (P-value for linearity=0.8). CONCLUSION: High levels of serum TF were not independently associated with an increased risk of future CAD in apparently healthy individuals.

Aged↗

PubMed2006

Relationship of alcohol intake and sex steroid concentrations in blood in pre- and post-menopausal women: the European Prospective Investigation into Cancer and Nutrition.

OBJECTIVE: Women with a moderate intake of alcohol have higher concentrations of sex steroids in serum, and higher risk of developing breast cancer, compared to non-drinkers. In the present study, we investigate the relationships between alcohol consumption and serum levels of sex steroids and sex-hormone binding globulin (SHBG) in 790 pre- and 1,291 post-menopausal women, who were part of the European Prospective Investigation into Cancer and Nutrition (EPIC). METHODS: Serum levels of testosterone (T), androstenedione (Delta4), dehydroepiandrosterone sulphate (DHEAS), estrone (E1), estradiol (E2) and SHBG were measured by direct immunoassays. Free T (fT) and free E2 (fE2) were calculated according to mass action laws. Current alcohol intake exposure to alcohol was assessed from dietary questionnaires. RESULTS: Pre-menopausal women who consumed more than 25 g/day of alcohol had about 30% higher DHEAS, T and fT, 20% higher Delta4 and about 40% higher E1, concentrations compared to women who were non-consumers. E2, fE2 and SHBG concentrations showed no association with current alcohol intake. In post-menopausal women, DHEAS, fT, T, Delta4, and E1 concentrations were between 10% and 20% higher in women who consumed more than 25 g/day of alcohol compared to non-consumers. E2 or fE2 were not associated with alcohol intake at all. SHBG levels were about 15% lower in alcohol consumers compared to non-consumers. CONCLUSION: This study supports the hypothesis of an influence of alcohol intake on sex hormone concentrations in blood.

Adult↗

PubMed2006

Dietary fish intake and plasma phospholipid n-3 polyunsaturated fatty acid concentrations in men and women in the European Prospective Investigation into Cancer-Norfolk United Kingdom cohort.

BACKGROUND: The n-3 polyunsaturated fatty acids (n-3 PUFAs) docosahexaenoic acid and eicosapentaenoic acid, found in fish and fish-oil supplements and also formed by conversion of alpha-linolenic acid in soy and rapeseed (canola) oils, are thought to have cardioprotective effects. OBJECTIVE: Because the relative feasibility and measurement error of dietary methods varies, this study compared fish and fish-oil intakes obtained from 4 dietary methods with plasma n-3 PUFAs in men and women in a general population. DESIGN: The study participants were 4949 men and women aged 40-79 y from the European Prospective Investigation into Cancer-Norfolk United Kingdom cohort. Measurements of plasma phospholipid n-3 PUFA concentrations and fish intakes were made with the use of 4 dietary methods (food-frequency questionnaire, health and lifestyle questionnaire, 7-d diary, and first-day recall from the 7-d diary). RESULTS: Amounts of fish consumed and relations with plasma phospholipid n-3 PUFAs were not substantially different between the 4 dietary methods. Plasma n-3 PUFA concentrations were significantly higher in women than in men, were 20% higher in fish-oil consumers than in non-fish-oil consumers, and were twice as high in fatty fish consumers as in total fish consumers. Only approximately 25% of the variation in plasma n-3 PUFA was explained by fish and fish-oil consumption. CONCLUSIONS: This large study found no substantial differences between dietary methods and observed clear sex differences in plasma n-3 PUFAs. Because variation in n-3 PUFA was only partially determined by fish and fish-oil consumption, this could explain the inconsistent results of observational and intervention studies on coronary artery disease protection.

Adult↗

PubMed2006

IGF-I, IGFBP-3 and breast cancer risk in women: The European Prospective Investigation into Cancer and Nutrition (EPIC).

Blood concentrations of insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) have recently been associated with breast cancer risk, notably in women who developed breast cancer at a young age. Prospective studies published so far, however, were relatively small and odds ratio (OR) estimates imprecise. We present the results of a large prospective case-control study nested within the European Prospective Investigation into Cancer and Nutrition on total IGF-I, IGFBP-3 and breast cancer risk including 1081 incident cases of invasive breast cancer and 2098 matched control subjects. Increasing IGF-I and IGFBP-3 concentrations were associated with a significant increase in breast cancer risk in women who developed breast cancer after 50 years of age (highest vs lowest quintile OR 1.38 (95% confidence interval (CI) 1.02-1.86), P = 0.01, and 1.44 (95% CI 1.04-1.98), P = 0.01, respectively), but no relationship was observed in younger women (OR = 1.03 (95% CI 0.60-1.77), P = 0.81 for IGF-I, and OR = 0.92 (95% CI 0.50-1.70), P = 0.69 for IGFBP-3). There was, however, significant heterogeneity in the relationship of breast cancer with serum IGF-I and IGFBP-3 levels depending on the time interval between blood donation and tumor diagnosis. A reduction in breast cancer risk with increasing IGF-I concentrations was observed in cases with a diagnosis of cancer less than 2 years after blood donation, (OR = 0.76 (95% CI 0.57-1.03)), while an increase in risk was observed for women with a later diagnosis (above or equal to two years after blood collection, OR = 1.51 (95% CI 1.19-1.91)). A similar pattern was observed for IGFBP-3. This study confirms previous findings for an association of serum IGF-I and IGFBP-3 concentrations with breast cancer risk, particularly for women with a later diagnosis of cancer, but it does not support the hypothesis of an involvement of IGF-I in younger women.

Adult↗

PubMed2005

Age at menarche in relation to adult height: the EPIC study.

In the last two centuries, age at menarche has decreased in several European populations, whereas adult height has increased. It is unclear whether these trends have ceased in recent years or how age at menarche and height are related in individuals. In this study, the authors first investigated trends in age at menarche and adult height among 286,205 women from nine European countries by computing the mean age at menarche and height in 5-year birth cohorts, adjusted for differences in socioeconomic status. Second, the relation between age at menarche and height was estimated by linear regression models, adjusted for age at enrollment between 1992 and 1998 and socioeconomic status. Mean age at menarche decreased by 44 days per 5-year birth cohort (beta = -0.12, standard error = 0.002), varying from 18 days in the United Kingdom to 58 days in Spain and Germany. Women grew 0.29 cm taller per 5-year birth cohort (standard error = 0.007), varying from 0.42 cm in Italy to 0.98 cm in Denmark. Furthermore, women grew approximately 0.31 cm taller when menarche occurred 1 year later (range by country: 0.13-0.50 cm). Based on time trends, more recent birth cohorts have their menarche earlier and grow taller. However, women with earlier menarche reach a shorter adult height compared with women who have menarche at a later age.

Adult↗

PubMed2005

The CAFE computer program for nutritional analysis of the EPIC-Norfolk food frequency questionnaire and identification of extreme nutrient values.

BACKGROUND: Food frequency questionnaires (FFQs) are widely used in nutritional epidemiology but no papers detail the development of the supporting programs and nutritional databases. The principles involved in data collection, processing and treatment of the European Prospective Investigation into Cancer Study (EPIC)-Norfolk Study FFQ and development of the structure and content of the Compositional Analyses from Frequency Estimates (CAFE) program for calculating nutrient intakes are described. Extreme nutrient values and derivation of cut-points for data exclusion are also discussed. METHODS: The FFQ was sent to 25,637 participants. To exclude extreme (nonphysiological) outliers of nutrient intakes, the extreme top and bottom 0.5% of the ratio of energy intake to estimated basal metabolic rate was used. RESULTS: The CAFE computer program modifies nutrient intake according to specific fats used in food preparation and the amount of visible fat on meat. It incorporates different breakfast cereals and distinguishes between text for brands and types. After exclusion of outliers of nutrient intake some extreme values remained for energy, carbohydrate, protein, fat and alcohol, because of high reported frequencies of certain foods. CONCLUSIONS: The features of CAFE include flexible, updateable, databases and a novel method for matching text. The effect of extreme nutrient values on the accuracy of the FFQ in estimating diet in nutritional epidemiology should be investigated further.

Adult↗

PubMed2004

Calcaneum broadband ultrasound attenuation relates to vegetarian and omnivorous diets differently in men and women: an observation from the European Prospective Investigation into Cancer in Norfolk (EPIC-Norfolk) population study.

Vegetarian diets have been suggested to be beneficial for bone health due to increased consumption of plant foods, including soya, or reduced consumption of meat. However, meat may also be beneficial for bone health. The evidence relating diet to bone health is based largely on studies of women, often in those at high risk of osteoporosis. Few studies have investigated dietary inter-relationships in men as well as women from general populations. We examined broadband ultrasound attenuation (BUA) of the calcaneum, using a CUBA clinical instrument, in 6,369 men and 5,379 postmenopausal women. The population was divided into four groups according to vegetarian status and frequency of soya consumption, which was defined by response to a food frequency questionnaire that estimates frequency of consumption of food types over the year prior to completion. Regular soya consumers were defined as those who ate soya products with a frequency of between once a day and once a week. Calcaneum BUA in vegetarian men was significantly lower than omnivores by approximately 6% (5 dB/MHz) and was 15% (13.6 dB/MHz) lower in those who were also regular soya consumers. This difference remained after adjustment for age, height, weight, smoking habit, physical activity, selected foods and nutrients and exclusion of those with a prior history of osteoporosis, fractures or cancer. Calcaneum BUA in omnivorous men with regular soya consumption was not lower than the remaining population. In women, there were no significant differences by usual dietary pattern. This surprising finding indicates that regular soya intake is not associated with better bone indices in vegetarian men. The difference in BUA was not explained by the known common covariates; however, it is possible that other aspects of lifestyle associated with these eating behaviors might explain this observation. Plausible mechanisms exist for our findings; soya contains phytoestrogens, likened to naturally occurring estrogens, and meat has been shown to influence levels of IGF-1 and sex hormone binding globulin, which may be related to bone health. Our findings emphasize the need for further research and investigation into dietary inter-relationships and bone health and the effects of vegetarian status, including consumption of soya-based foods, in men as well as women.

Adult↗

PubMed2004

Correlated measurement error--implications for nutritional epidemiology.

BACKGROUND: In nutritional epidemiology, it is common to fit models in which several dietary variables are included. However, with standard instruments for dietary assessment, not only are the intakes of many nutrients often highly correlated, but the errors in the estimation of the intake of different nutrients are also correlated. The effect of this error correlation on the results of observational studies has been little investigated. This paper describes the effect on multivariate regression coefficients of different levels of correlation, both between the variables themselves and between the errors of estimation of these variables. METHODS: Using a simple model for the multivariate error structure, we examine the effect on the estimates of bivariate linear regression coefficients of (1) differential precision of measurement of the two independent variables, (2) differing levels of correlation between the true values of the two variables, and (3) differing levels of correlation between the errors of measurement of the two variables. As an example, the prediction of plasma vitamin C levels by dietary intake variables is considered, using data from the European Prospective Investigation of Cancer (EPIC) Norfolk study in which dietary intake was estimated using both a food frequency questionnaire (FFQ) and a 7-day diary (7DD). The dietary variables considered are vitamin C, fat, and energy, with different approaches taken to energy adjustment. RESULTS: When the error correlation is zero, the estimates of the bivariate regression coefficients reflect the precision of measurement of the two variables and mutual confounding. The sum of the observed regression coefficients is biased towards the null as in univariate regression. When the error correlation is non-zero but below about 0.7, the effect is minor. However, as the error correlation increases beyond 0.8 the effect becomes large and highly dependent on the relative precision with which the two variables are measured. At the extreme, the bivariate estimates can become indefinitely large. In the example, the error correlation between fat and energy using the FFQ appears to be over 0.9, the corresponding value for the 7DD being approximately 0.85. The error correlation between vitamin C and fat, and vitamin C and energy, appears to be below 0.5 and smaller for the 7DD than for the FFQ. The impact of these error correlations on bivariate regression coefficients is large. The effect of energy adjustment differs widely between vitamin C and fat. CONCLUSION: High levels of error correlation can have a large effect on bivariate regression estimates, varying widely depending on which two variables are considered. In particular, the effect of energy adjustment will vary widely. For vitamin C, the effect of energy adjustment appears negligible, whereas for fat the effect is large indicating that error correlation close to one can partially remove regression dilution due to measurement error. If, for fat intake, energy adjustment is performed by using energy density, the partial removal of regression dilution is achieved at the expense of substantial reduction in the true variance.

Ascorbic Acid↗

PubMed2004

Abdominal obesity and respiratory function in men and women in the EPIC-Norfolk Study, United Kingdom.

Poor respiratory function and obesity are associated with all-cause and cardiovascular disease mortality. Obese persons may also have impaired lung function, but the mechanism is unclear. The authors investigated the relation between abdominal pattern of obesity and respiratory function in the European Prospective Investigation into Cancer and Nutrition-Norfolk (EPIC-Norfolk) cohort in Norfolk, United Kingdom. This analysis included 9,674 men and 11,876 women aged 45-79 years with no known preexisting serious illness who had complete anthropometric and respiratory function measures obtained at a health visit between 1993 and 1997. Waist:hip ratio was used to assess abdominal obesity, and forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC), obtained by spirometry, were used to assess respiratory function. Both FEV1 and FVC were linearly and inversely related across the entire range of waist:hip ratio in both men and women. This relation persisted after adjustment for age, body mass index, cigarette smoking, social class, physical activity index, prevalent bronchitis/emphysema, and prevalent asthma. The association remained significant among nonobese nonsmokers without preexisting respiratory disease. In the general adult population, abdominal fat deposition may play a role in the impairment of respiratory function among the abdominally obese.

Abdomen↗

PubMed2004

An association between respiratory function and hip bone mineral density in older men: a cross-sectional study.

The association between respiratory function and bone mineral density (BMD) among women living in the community has been reported previously. We examined the association between forced expiratory volume in 1 s (FEV(1)) and BMD measured at hip using dual-energy X-ray absorptiometry in a group of 947 men (aged 65 to 76 years) recruited from general practice age-sex registers in Cambridge between 1991 and 1995. A positive and significant correlation was seen between FEV(1) and BMD measured at total hip, femoral neck, and trochanter. A unit change (1 l) in FEV(1) was associated with a change of BMD by 0.019, 0.017, and 0.026 g/cm(2) in the total hip, femoral neck, and tochanteric region, respectively. These associations were independent of possible confounding factors such as age, height, weight, smoking habit, major disease prevalence, and medications, which might affect bone metabolism. In categorical analyses, the highest BMD was seen in the highest FEV(1) quartile, while the lowest BMD was seen in the lowest FEV(1) quartile. This pattern was seen in all three skeletal sites and was independent of covariates listed above. Compared with the bottom FEV(1) quartile, mean hip BMDs in the top quartile were 2-3.5% higher. The exact mechanism of this association is not clear to us. One plausible explanation is that respiratory function and bone health both reflect common but as yet unknown determinants.

Aged↗

PubMed2004

Broadband ultrasound attenuation (BUA) of the heel bone and its correlates in men and women in the EPIC-Norfolk cohort: a cross-sectional population-based study.

Osteoporotic fractures have substantial clinical and public health impact. Bone quality is an important determinant of fracture risk. Quantitative ultrasound (QUS) of bone measured as broadband ultrasound attenuation (BUA) has been shown to predict fracture risk. However, there have been very few large population studies, particularly in men. We investigated the correlates of calcaneal BUA using a CUBA clinical machine in 15,668 middle and older aged men and women (42-82 years) from the UK, EPIC-Norfolk cohort. At all ages mean BUA was significantly greater in men than women (men, 90.1+/-17.6; women 72.1+/-16.5). The age-related decline in BUA was five times greater in women than men (-0.77 vs. -0.15 dB/MHz per year). Pre- and post-menopausal bone loss was 0.39 and 0.85 dB/MHz per year, respectively. In univariate regression BUA increased with weight and height by 0.45 dB/MHz per kg and 0.68 per cm in women and 0.24 dB/MHz per kg and 0.33 per cm in men. BUA increased with body mass index (BMI) by 0.84 dB/MHz per kg/m2 in women and 0.55 in men. However, weight was twice as influential as height in men and seven times as great in women. Age, weight and height explained 27% of the variance of BUA in women, but only 3% in men. Adjusted BUA was significantly lower in men and women with an existing history of any hip, wrist or spinal fracture both overall and when analysed for specific site. Figures were: all fractures 66.8 vs. 72.5 dB/MHz ( P<0.001), women; 84.1 vs. 90.5 ( P<0.001), men; hip fractures 61.9 vs. 72.2 dB/MHz ( P<0.001), women; 81.5 vs. 90.2 ( P<0.001), men; wrist fractures 66.6 vs. 72.5 dB/MHz ( P<0.001), women; 81.5 vs. 90.2 ( P<0.001), men; spinal fractures 68.1 vs. 72.1 dB/MHz ( P<0.01), women; 85.1 vs. 90.2 ( P<0.01), men. These differences equate to reductions of 14, 9 and 6% and 10, 7 and 6% for fractures of the hip, wrist and spine in the BUA of women and men, respectively. Thus, despite the overall gender difference in BUA the relative magnitude of a previous history of fracture was equally important in both men and women. Adjusted BUA was also lower in those with previous history of osteoporosis. In women currently taking hormone replacement therapy (HRT) the adjusted BUA was 5 dB/MHz or one-third of an SD greater than in those who did not. The BUA of those with a current smoking habit was 1.7% lower in women and 3.2% lower in men. Overall, there are substantial sex differences in the relationship of the physical and osteoporotic risk factors associated with BUA. A better understanding of these determinants of heel ultrasound may provide insights into how some of the sex differences in bone health can be explained and bone loss in later life minimised.

Adult↗

PubMed2004

Area deprivation predicts lung function independently of education and social class.

The cross-sectional association between socioeconomic status (at both the individual and area-based level) and lung function, as measured by forced expiratory volume in one second, in a large population-based cohort was investigated. The study population consisted of 22,675 males and females aged 39-79 yrs. They were recruited from the general community in Norfolk, UK using general practice age/sex registers, as part of the European Prospective Investigation into Cancer (EPIC-Norfolk). It was found that being in a manual occupational social class, having no educational qualifications and living in a deprived area all independently predicted significantly lower lung function, even after controlling for smoking habit. The influence of area-deprivation on lung function, independent of individual socioeconomic status and of individual smoking habit, suggests that apart from targeting individuals who are at high-risk, such as smokers, environmental determinants also need to be examined when considering measures to improve respiratory health.

Adult↗

PubMed2003

Hip section modulus, a measure of bending resistance, is more strongly related to reported physical activity than BMD.

We hypothesized that measures of physical activity would have a closer relationship with section modulus (SM), an indicator of bending resistance, than with bone mineral density (BMD) because physical activity might expand the bony envelope, which tends to reduce BMD for a constant bone mineral content. Four hundred twenty-three men and 436 women (mean age 72 years, SD =3) were recruited from a prospective population-based cohort study to a study of hip bone loss. Hip BMD was measured on two occasions 2-5 years apart (mean 2.7, DXA-Hologic 1,000 W). Hip structural analysis (HSA) software was used to calculate SM and BMD from the DXA scans on three narrow regions: the narrow neck (NN), intertrochanter (IT) and shaft (S). A physical activity and lifestyle questionnaire was administered at baseline. Multivariate repeated measures analysis of variance was used to model the associations between personal attributes (weight, height, age), physical activity and lifestyle variables with SM, cross-sectional area (CSA), sub-periosteal diameter (PD) and BMD. Men and women were analysed together after tests for interactions with gender, which were found not to be significant. In all regions female gender was associated with having lower values of all outcomes, and body weight was positively associated with all outcomes, i.e., SM, CSA, PD and BMD ( P<0.0001). Sub-periosteal diameter was positively associated with reported lifetime physical activity (IT and S, P<0.0001). There was a significant decline of BMD with age at the NN and S regions ( P<0.026), and the PD increased with age (NN and S, P<0.019). Previous fracture history was associated with having lower values of BMD, SM and CSA (except for S; P<0.022). Both section modulus and CSA were positively associated with heavy physical activity after age 50 years in all regions ( P<0.019), whereas NN BMD was the only BMD associate of heavy physical activity after 50 ( P=0.036). Time spent per week on recreational activities classified as no impact activity was positively associated with BMD, CSA and SM (multivariate P<0.016). In conclusion, proximal femur diameter is associated positively with reported life-long physical activity. If this is mediated through a loading related effect on sub-periosteal expansion, BMD would be an unsatisfactory outcome measure in physical activity studies since it is inversely related to projected bone area. SM in contrast was associated with several measures of recent physical activity and relates more directly to the bending experienced by the proximal femur in response to a given load. These data are consistent with an effect of mechanical loading to regulate bone strength through an anabolic effect maximal in the subperiosteal cortex, where the highest loading-related strains are experienced.

Absorptiometry, Photon↗

PubMed2003

The diagnostic contribution of the frontal lumbar spine radiograph in community referred low back pain--a prospective study of 1030 patients.

AIM: The diagnostic contribution of the anteroposterior (AP) view was studied to assess whether this view could be omitted safely, thus reducing the radiation burden received by patients undergoing lumbar spine radiography. MATERIALS AND METHODS: Prospective analysis of 1030 consecutive referrals for lumbar spine radiography from general practice. RESULTS: In the majority of cases (90.5%) the AP view was non-contributory. In 4.2% the diagnosis was strengthened and it was altered in 4.6%. However, in the latter group only 1.3% of the total were considered significant alterations. These were cases of possible, but not definite, pars defects and sacroiliitis. Specific important conditions such as infection, malignancy and benign tumours were not missed on the lateral view alone, in our study population. The radiation burden is reduced by 75% by omitting the AP view. CONCLUSION: A single lateral view is an adequate examination, with the proviso that sacroiliac joint disease is not assessed on this view and some pars defects and facet joint degenerative changes may be overlooked. The radiation protection gains are considerable. A single lateral lumbar view is now our routine practice unless sacroiliitis is a specific clinical concern.

Adolescent↗

PubMed2002

An association between respiratory function and bone mineral density in women from the general community: a cross sectional study.

Respiratory function has been associated with bone mineral density (BMD) in patients with respiratory diseases. We examined the relationship between bone density measured at the hip and respiratory function in women from the general community. A total of 4830 women aged 45-76 years were recruited from general practice age-sex registers in Cambridge between 1991 and 1995. At baseline survey, data collection included health questionnaires, measures of anthropometry, respiratory function, as well as bone mineral density BMD measured using dual energy X ray absorptiometry. BMD at total hip, femoral neck and trochanter significantly and positively correlated with FEV(1). This association was independent of age, weight, height, smoking habit, history of respiratory diseases, corticosteroids and use of hormone replacement therapy. After adjustment for these factors, an increase in FEV(1) of 1 l/s was associated with 0.026, 0.021 and 0.026g/cm(2) increase in bone mineral density at total hip, femoral neck and trochanter respectively. The association was consistent and similar in magnitude among current smokers and current non-smokers and across all age groups. The magnitude of the association was comparable to that associated with an age difference of 6 years or weight difference of 5 kg. Women in the bottom compared to top quartile of respiratory function had about double the risk of low bone density independent of other factors. Respiratory function measured using FEV(1) is positively and independently related to BMD in these middle-aged and older women across the whole normal distribution of these physiologic measures. This may reflect underlying common determinants such as physical activity. Even in healthy women, respiratory function may be a marker for women at increased risk of osteoporosis and associated fractures.

Aged↗

PubMed2002

Improving risk assessment: hip geometry, bone mineral distribution and bone strength in hip fracture cases and controls. The EPOS study. European Prospective Osteoporosis Study.

Hip geometry and bone mineral density (BMD) have previously been shown to relate independently to hip fracture risk. Our objective was to determine by how much hip geometric data improved the identification of hip fracture. Lunar pencil beam scans of the proximal femur were obtained. Geometric and densitometric values from 800 female controls aged 60 years or more (from population samples which were participants in the European Prospective Osteoporosis Study, EPOS) were compared with data from 68 female hip fracture patients aged over 60 years who were scanned within 4 weeks of a contralateral hip fracture. We used Lunar DPX 'beta' versions of hip strength analysis (HSA) and hip axis length (HAL) applied to DPX(L) data. Compressive stress (Cstress), calculated by the HSA software to occur as a result of a typical fall on the greater trochanter, HAL, body mass index (BMI: weight/(height)2) and age were considered alongside femoral neck BMD (FN-BMD, g/cm2) as potential predictors of fracture. Logistic regression was used to generate predictors of fracture initially from FN-BMD. Next age, Cstress (as the most discriminating HSA-derived parameter), HAL and BMI were added to the model as potentially independent predictors. It was not necessary to include both HAL and Cstress in the logistic models, so the entire data set was examined without excluding the subjects missing HAL measurements. Cstress combined with age and BMI provided significantly better prediction of fracture than FN-BMD used alone as is current practice, judged by comparing areas under receiver operating characteristic (ROC) curves (p<0.001, deLong's test). At a specificity of 80%, sensitivity in identification was improved from 66% to 81%. Identifying women at high risk of hip fracture is thus likely to be substantially enhanced by combining bone density with age, simple anthropometry and data on the structural geometry of the hip. HSA might prove to be a valuable enhancement of DXA densitometry in clinical practice and its use could justify a more proactive approach to identifying women at high risk of hip fracture in the community.

Absorptiometry, Photon↗

PubMed2002

Overweight, obesity and fat distribution in 50- to 64-year-old participants in the European Prospective Investigation into Cancer and Nutrition (EPIC).

OBJECTIVE: To describe anthropometric characteristics of participants of the European Prospective Investigation into Cancer and Nutrition (EPIC). DESIGN: A cross-sectional analysis of baseline data of a European prospective cohort study. SUBJECTS: This analysis includes study populations from 25 centres in nine European countries. The British populations comprised both a population-based and a 'health-conscious' group. The analysis was restricted to 83 178 men and 163 851 women aged 50-64 years, this group being represented in all centres. METHODS: Anthropometric examinations were undertaken by trained observers using standardised methods and included measurements of weight, height, and waist and hip circumferences. In the 'health-conscious' group (UK), anthropometric measures were predicted from self-reports. RESULTS: Except in the 'health-conscious' group (UK) and in the French centres, mean body mass index (BMI) exceeded 25.0 kg m-2. The prevalence of obesity (BMI> or =30 kg m(-2)) varied from 8% to 40% in men, and from 5% to 53% in women, with high prevalences (>25%) in the centres from Spain, Greece, Ragusa and Naples (Italy) and the lowest prevalences (<10%) in the French centres and the 'health-conscious' group (UK). The prevalence of a large waist circumference or a high waist-to-hip ratio was high in centres from Spain, Greece, Ragusa and Naples (Italy) and among women from centres in Germany and Bilthoven (The Netherlands). CONCLUSIONS: Anthropometric measures varied considerably within the EPIC population. These data provide a strong base for further investigation of anthropometric measures in relation to the risk of chronic diseases, especially cancer.

Adipose Tissue↗