Occupational social class, educational level and area deprivation independently predict plasma ascorbic acid concentration: a cross-sectional population based study in the Norfolk cohort of the European Prospective Investigation into Cancer (EPIC-Norfolk)

OBJECTIVE

To investigate the independent association between three different measures of socioeconomic status and plasma ascorbic acid level.

DESIGN

Cross-sectional population based study.

SETTING AND PARTICIPANTS

20 292 men and women aged 39-79 y who participated in the EPIC-Norfolk study.

RESULTS

Individuals in manual social classes, who had no educational qualifications or those who lived in the most deprived areas had significantly lower levels of plasma ascorbic acid compared to those in nonmanual social classes, with at least O-level qualifications or who lived in less deprived areas. The magnitude of effect for each measure of socioeconomic status was greater in current smokers compared to current nonsmokers.

CONCLUSION

Education and social class were stronger predictors of differences in ascorbic acid levels, an indicator of dietary health behaviour, than a deprivation index based on the Townsend score. This suggests that education could be particularly important in influencing large socioeconomic differentials in health related behaviours and potentially, health outcomes in the UK.

Traditional cardiovascular risk factors measured prior to the onset of inflammatory polyarthritis

BACKGROUND

Cardiovascular mortality is increased in patients with seropositive inflammatory polyarthritis (IP). We tested the hypothesis that the increased risk of cardiovascular disease (CVD) can be explained by elevated traditional CVD risk factor levels in persons prior to development of IP.

METHODS

In a population-based, prospective nested case-control study, 25 600 people aged 45-75 yr participated in a health survey, including standard CVD risk factor assessment, between the years 1993 and 1997. There were 91 incident IP cases (one-third were seropositive at presentation) identified during follow-up to the end of July 2001. Baseline CVD risk factors in the IP cases were compared with those in two age/gender-matched controls.

RESULTS

Current smokers had an odds ratio of 2.0 (95% CI 1.0-4.0) for IP. Other risk factors, including total and LDL cholesterol, systolic and diastolic blood pressure and obesity, did not differ significantly between cases and controls. Importantly, in combination, using a standard coronary disease risk score, these factors only had a modest association with future IP, and no association when analysis was restricted to the smaller number of cases who were seropositive.

CONCLUSION

Of the traditional cardiovascular risk factors, only smoking increases CVD risk prior to the onset of IP. Therefore the increased CVD observed in these patients is likely to be a consequence of factors operating after the onset of the arthritis.

Vitamin K and childhood cancer: a report from the United Kingdom Childhood Cancer Study

The relationship between neonatal vitamin K received by the intramuscular (i.m.) route and the development of leukaemia or other cancers was investigated as part of a national case–control study of childhood cancer, using data abstracted from obstetric and neonatal records. The analyses included 2530 children diagnosed with cancer before 15 years of age, 1174 of whom had leukaemia and 4487 control children without cancer. Overall, 39% of cases and 42% of controls had records of i.m. vitamin K administration, while 24% of cases and 22% of controls had no record of whether or not they had received vitamin K. Using subjects who received i.m. vitamin K as the baseline group, our analyses found no association between the administration of i.m. vitamin K and either leukaemia or other cancers as a group. We conclude that there is no convincing evidence that neonatal vitamin K administration, irrespective of the route by which it is given, influences the risk of children developing leukaemia or any other cancer.

Residential area deprivation predicts smoking habit independently of individual educational level and occupational social class. A cross sectional study in the Norfolk cohort of the European Investigation into Cancer (EPIC-Norfolk)

OBJECTIVES

To investigate the independent association between individual and area based measures of socioeconomic status and cigarette smoking habit.

DESIGN AND SETTING

Cross sectional, population based study.

PARTICIPANTS AND METHODS

12 579 men and 15 132 women aged 39-79 years living in the general community participating in the EPIC-Norfolk Study in 1993-1997. The association between social class, educational status, Townsend residential deprivation level, and cigarette smoking status was examined.

MAIN OUTCOME MEASURES

Cigarette smoking status at baseline survey.

RESULTS

Social class, educational level, and residential deprivation level independently related to cigarette smoking habit in both men and women. Multivariate age adjusted odds ratios for current smoking in men were 1.62 (95% CI 1.45 to 1.81) for manual compared with non-manual social class, 1.32 (95% CI 1.17 to 1.48) for those with educational level less than O level compared with those with O level qualifications or higher and 1.84 (95% CI 1.62 to 2.08) for high versus low area deprivation level. For women, the odds ratios for current smoking for manual social class were 1.14 (95% CI 1.03 to 1.27); 1.31 (95% CI 1.18 to 1.46) for low educational level and 1.68 (95% CI 1.49 to 1.90) for high residential deprivation respectively.

CONCLUSIONS

Residential deprivation level using the Townsend score, individual social class, and educational level all independently predict smoking habit in both men and women. Efforts to reduce cigarette smoking need to tackle not just individual but also area based factors. Understanding the specific factors in deprived areas that influence smoking habit may help inform preventive efforts.

5-HT(2B) receptors play a key role in mediating the excitatory effects of 5-HT in human colon in vitro

1. 5-Hydroxytryptamine (5-HT) is known to produce a number of different effects in the gastrointestinal tract of various species, and has been proposed to play a key role in a number of intestinal disorders in man, including irritable bowel syndrome (IBS), although the receptors involved have yet to be established. The aim of the present study was to investigate the distribution and function of 5-HT(2B) receptors in human colon, and to establish their possible role in the aetiology of IBS. 2. The distribution of 5-HT(2B) receptor mRNA and protein were investigated by quantitative RT - PCR, Western analysis and immunocytochemistry. High levels of both mRNA and protein for 5-HT(2B) receptors were found throughout the human gastrointestinal tract, and in particular in colon, where 5-HT(2B) receptors were found predominantly in the longitudinal and circular smooth muscle layers within the muscularis externa, and in the myenteric nerve plexus lying between these two layers. 3. Electrical field stimulation of longitudinal muscle preparations of human colon mounted in organ baths resulted in neuronally-mediated contractile responses, that were significantly potentiated by application of 5-HT (up to 10(-7) M), with a pEC(50) of 8.2 +/- 0.1 (n=49 donors). The response to 5-HT was inhibited by a number of selective 5-HT(2B) receptor antagonists. 4. This study has shown for the first time that, in contrast to animal studies, the excitatory effects of 5-HT in human colon are mediated by 5-HT(2B) receptors. It is proposed that these receptors contribute to the putative 5-HT-induced colonic smooth muscle hypersensitivity associated with IBS.

Carbohydrate deficient transferrin in abstaining patients with end-stage liver disease

BACKGROUND

Carbohydrate deficient transferrin (CDT), a biochemical marker of chronic alcohol consumption, is used by researchers and clinicians alike in a variety of populations. Levels of CDT may be affected by certain types of medical illnesses and conditions. Thus the interpretation of CDT results may need to be carefully examined in these populations. Because CDT is synthesized, glycosylated, and secreted by the liver, the use of CDT values in patients with liver disease has been an area of focused interest.

METHODS

We evaluated the CDT values of 79 abstaining patients with end-stage liver disease. These patients were recruited from a liver transplant clinic while they were listed and waiting for transplantation. Patients were determined to be abstaining both by interview and by random blood alcohol levels in those with a diagnosis of alcoholic liver disease. The severity of the liver disease was categorized by the Child-Pugh score. Correlations were determined between CDT values and liver enzymes, and Child-Pugh scores and liver diagnosis.

RESULTS

Nearly 50% of the patients had a CDT value of 2.6% or above, indicating a clinically positive value. There were strong correlations between CDT and a number of biochemical and physical variables, most importantly the Child-Pugh score (r = 0.52, p = 0.000). Specific liver diseases were not associated with absolute CDT values. However, patients with hepatitis C (HCV) had a significantly higher chance of having a clinically positive CDT compared with patients with other types of liver diseases.

CONCLUSIONS

These results suggest that an elevated CDT value may not accurately represent alcohol consumption in patients with advanced liver disease. In fact, in such patients, the CDT may become a marker for the degree of liver impairment in alcoholic and nonalcoholic liver disease. CDT values should be viewed with caution in any patient with liver disease especially when the degree of cirrhosis reaches a Child-Pugh score of C (total score of 10 or above).

Carbohydrate deficient transferrin in abstaining patients with end-stage liver disease

BACKGROUND

Carbohydrate deficient transferrin (CDT), a biochemical marker of chronic alcohol consumption, is used by researchers and clinicians alike in a variety of populations. Levels of CDT may be affected by certain types of medical illnesses and conditions. Thus the interpretation of CDT results may need to be carefully examined in these populations. Because CDT is synthesized, glycosylated, and secreted by the liver, the use of CDT values in patients with liver disease has been an area of focused interest.

METHODS

We evaluated the CDT values of 79 abstaining patients with end-stage liver disease. These patients were recruited from a liver transplant clinic while they were listed and waiting for transplantation. Patients were determined to be abstaining both by interview and by random blood alcohol levels in those with a diagnosis of alcoholic liver disease. The severity of the liver disease was categorized by the Child-Pugh score. Correlations were determined between CDT values and liver enzymes, and Child-Pugh scores and liver diagnosis.

RESULTS

Nearly 50% of the patients had a CDT value of 2.6% or above, indicating a clinically positive value. There were strong correlations between CDT and a number of biochemical and physical variables, most importantly the Child-Pugh score (r = 0.52, p = 0.000). Specific liver diseases were not associated with absolute CDT values. However, patients with hepatitis C (HCV) had a significantly higher chance of having a clinically positive CDT compared with patients with other types of liver diseases.

CONCLUSIONS

These results suggest that an elevated CDT value may not accurately represent alcohol consumption in patients with advanced liver disease. In fact, in such patients, the CDT may become a marker for the degree of liver impairment in alcoholic and nonalcoholic liver disease. CDT values should be viewed with caution in any patient with liver disease especially when the degree of cirrhosis reaches a Child-Pugh score of C (total score of 10 or above).

Estimation of disease progression parameters from case-control data: application to mammographic patterns and breast cancer natural history

BACKGROUND

Estimations of mean sojourn time (MST) and sensitivity (S) in disease screening have been previously calculated from case-control data, using simple models which did not include covariates. Many studies have shown an effect of mammographic parenchymal pattern (MPP) on breast-cancer risk and tumour histology. We have expanded previous models on these to estimate MST and S with the effects of MPP as a covariate.

METHODS

Data were from a nested case-control study within the East Anglian screening programme, with 875 cases and 2,601 controls. Estimates of disease progression and screening parameters were based on conditional likelihood calculation, using a Markov process model. Ninety-five per cent confidence intervals (CI) were calculated using the profile likelihood wherever possible and using a numerical estimate of the information matrix or the area under the likelihood curve where necessary.

RESULTS

We obtained estimates of the incidence of preclinical disease, rate of transition from preclinical to clinical and screening sensitivity, and evaluated the association of these parameters with mammographic parenchymal pattern. A higher incidence of preclinical disease was found for high-risk MPP [relative incidence = 1.62 (95% CI: 0.89; 2.73)]. However, no difference in progression rate from preclinical to clinical disease between different MPP was found. Dense MPPs were associated with decreased sensitivity [relative sensitivity = 0.24 (95% CI: 0.06; 15)]. Wide CIs were found, probably being a consequence of the relative sparsity of interval cancer data.

DISCUSSION

It is possible to estimate multiple parameters of disease progression and screening quality from case-control data. The reduction in sensitivity of the screening process associated with high-risk patterns presented here, could be of paramount interest for proposing new screening strategies, such as possible additional screening tools.

Frequency of eating and concentrations of serum cholesterol in the Norfolk population of the European prospective investigation into cancer (EPIC-Norfolk): cross sectional study

OBJECTIVES

To examine the relation between self reported eating frequency and serum lipid concentrations in a free living population.

DESIGN

Cross sectional population based study.

SETTING

Norfolk, England.

PARTICIPANTS

14 666 men and women aged 45-75 years from the Norfolk cohort of the European prospective investigation into cancer (EPIC-Norfolk).

MAIN OUTCOME MEASURES

Concentrations of blood lipids.

RESULTS

Mean concentrations of total cholesterol and low density lipoprotein cholesterol decreased in a continuous relation with increasing daily frequency of eating in men and women. No consistent relation was observed for high density lipoprotein cholesterol, body mass index, waist to hip ratio, or blood pressure. Mean cholesterol concentrations differed by about 0.25 mmol/l between people eating more than six times a day and those eating once or twice daily; this difference was reduced to 0.15 mmol/l after adjustment for possible confounding variables, including age, obesity, cigarette smoking, physical activity, and intake of energy and nutrients (alcohol, fat, fatty acids, protein, and carbohydrate).

CONCLUSIONS

Concentrations of total cholesterol and low density lipoprotein cholesterol are negatively and consistently associated with frequency of eating in a general population. The effects of eating frequency on lipid concentrations induced in short term trials in animals and human volunteers under controlled laboratory conditions can be observed in a free living general population. We need to consider not just what we eat but how often we eat.

Protein kinase Calpha plays a critical role in mannosylerythritol lipid-induced differentiation of melanoma B16 cells

Mannosylerythritol lipid (MEL), a novel extracellular glycolipid from yeast, was found to inhibit the proliferation of mouse melanoma B16 cells in a dose-dependent manner and to induce the apoptosis of B16 cells at concentrations higher than 10 microm (Zhao, X., Wakamatsu, Y., Shibahara, M., Nomura, N., Geltinger, C., Nakahara, T., Murata, T., and Yokoyama, K. K. (1999) Cancer Res. 59, 482-486). We show here that exposure of B16 cells to MEL (5 microm) for 2 days resulted in an increase of the levels of differentiation-associated markers of melanoma cells such as melanogenesis and tyrosinase activity, which were accompanied by morphological changes. The MEL-induced differentiation of B16 cells at this concentration was closely associated with arrest of the cell cycle at G(1) phase, but no significant population of apoptotic cells was identified. Expression of protein kinase Calpha (PKCalpha) was enhanced after exposure of B16 cells to MEL for 48 h. Antisense oligodeoxynucleotides against the mouse gene for PKCalpha prevented MEL-induced melanogenesis in B16 cells. Conversely, the effects of the expression of a constitutively active form of PKCalpha mimicked the effects of MEL on B16 cells. These data suggest that MEL, a yeast-derived glycolipid, triggers the differentiation of B16 melanoma cells through a signaling pathway that involves PKCalpha.

Epidemiological assessment of diet: a comparison of a 7-day diary with a food frequency questionnaire using urinary markers of nitrogen, potassium and sodium

BACKGROUND

Validation studies of dietary instruments developed for epidemiological studies have typically used some form of diet record as the standard for comparison. Recent work suggests that comparison with diet record may overestimate the ability of the epidemiological instrument to measure habitual dietary intake, due to lack of independence of the measurement errors. The degree of regression dilution in estimating diet-disease association may therefore have been correspondingly underestimated. Use of biochemical measures of intake may mitigate the problem. In this paper, we report on the use of urinary measures of intakes of nitrogen, potassium and sodium to compare the performance of a semi-quantitative food frequency questionnaire (FFQ) and a 7-day diet diary (7DD) to estimate average intake of these nutrients over one year.

METHODS

In all, 179 individuals were asked to complete an FFQ and a 7DD on two occasions separated by approximately 12 months. The individuals were also asked to provide 24-hour urine samples on six occasions over a 6-9-month period, covering the time at which the record FFQ and 7DD were completed. The urine was assayed for nitrogen, potassium and sodium. The protocol was completed by 123 individuals. The data from these individuals were analysed to estimate the covariance structure of the measurement errors of the FFQ, the 7DD and a single 24-hour urine measurement, and to estimate the degree of regression dilution associated with the FFQ and 7DD.

RESULTS

The results demonstrated that: (1) the error variances for each of the three nutrients was more than twice as great with the FFQ than the 7DD; (2) there was substantial correlation (0.46-0.58) between the error of both the FFQ and the 7DD completed on different occasions; (3) there was moderate correlation (0.24- 0.29) between the error in the FFQ and the error in the 7DD for each nutrient; (4) the correlation between errors in different nutrients was higher for the FFQ (0.77-0.80) than for the 7DD (0.52-0.70).

CONCLUSIONS

The regression dilution with the FFQ is considerably greater than with the 7DD and also, for the nutrients considered, greater than would be inferred if validation studies were based solely on record or diary type instruments.

Mammographic parenchymal patterns and breast cancer natural history--a case-control study

The relationship between tumour size, malignancy grade and dense mammographic parenchymal patterns was evaluated by using a nested case-control design with 875 breast cancer cases and 2 601 matched controls. Wolfe's classification was used to assess mammographic parenchymal patterns. The dense P2/DY mammographic parenchymal patterns were significantly associated with invasive ductal grade 3 carcinoma (OR = 2.03; 95%, CI 1.13-3.62, p = 0.016). Stratified by tumour size, we found that the odds ratio for grade 3 invasive ductal NOS breast cancer measuring 15-19 mm associated with P2/DY mammographic parenchymal patterns was 3.46 (95% CI 1.12-10.68). For tumours larger than 30 mm, the odds ratio was 10.09 (95% CI 1.27-79.93). The highest risk of grade 3 cancers being in tumours measuring 30 mm + may be due to dedifferentiation of missed cancers, but there is some excess even in the < 20 mm tumours, suggesting an increased risk in association with dense mammographic patterns of some aggressive cancers which are grade 3 at inception. Our results are consistent with the model that breast cancer is a progressive disease, whose development can be arrested by screening, and that the point at which individual tumour progression is stopped is crucial for prognosis not simply in terms of stage of disease, but also of histological grade.

Simultaneous detection of RNA and protein by in situ hybridization and immunological staining

Proteinase K is widely used in methods for detection of transcripts in biological specimens by in situ hybridization (ISH). However, treatment with proteinase K hampers detection of RNA and protein simultaneously. We have developed a method for double staining of transcripts and proteins by ISH and IHC staining in imaginal discs and embryos of Drosophila. Instead of treatment with proteinase K, samples are treated with ethanol plus xylene and with acetone. Acetone renders cell membranes permeable to probes and antibodies without damaging tissue integrity, whereas treatment with proteinase K sometimes damages tissues. Treatment of samples with acetone allows hybridization of probe with transcripts in tissue. It is also effective for immunological staining of samples after ISH with a riboprobe. Thus, our method allows detection not only of transcripts but also of specific proteins in relatively intact single samples. (J Histochem Cytochem 49:1177-1182, 2001)

Intercellular communication in cultured human vascular smooth muscle cells

Intercellular communication through gap junction channels plays a fundamental role in regulating vascular myocyte tone. We investigated gap junction channel expression and activity in myocytes from the physiologically distinct vasculature of the human internal mammary artery (IMA, conduit vessel) and saphenous vein (SV, capacitance vessel). Northern and Western blots documented the presence of connexin43 (Cx43) in frozen tissues and cultured cells from both vessels. Northern blots also confirmed the presence of Cx40 mRNA in cultured IMA and SV myocytes. Dual whole cell patch-clamp experiments revealed that macroscopic junctional conductance was voltage dependent and characteristic of that observed for Cx43. In the majority of records, in both vessels, single-channel activity was dominated by a main-state conductance of 120 pS, with subconducting events comprising less than 10% of the amplitude histograms. However, some records showed "atypical" unitary events that had a conductance similar to Cx40 (approximately 140-160 pS), but gating behavior like that of Cx43. As such, it is conceivable that the presence and coexpression of Cx40 and Cx43 in IMA and SV myocytes may result in heteromeric channel formation. Nonetheless, in terms of gating, Cx43-like behavior clearly dominates.

Alcohol use following liver transplantation: a comparison of follow-up methods

Alcoholic cirrhosis is one of the most common indications for liver transplantation. Previous researchers have studied rates of return to drinking following transplantation, however, few have employed prospective measures of alcohol use. The authors prospectively studied the alcohol use of patients transplanted for alcoholic liver disease. The authors improved the accuracy of monitoring alcohol use by using various methods for tracking patient's alcohol consumption, and we report on the time to first alcohol use after transplantation comparing these different methods. The authors found that alcohol use can occur very early after transplantation, even within the first 3 months posttransplant. Thirty-eight percent of the patients consumed any alcohol after transplantation. The clinical interviews by the psychiatrist were the most successful method for identifying posttransplant alcohol use. Posttransplant alcohol use was significantly associated with prior nonalcohol substance use (P < 0.025), family history of alcoholism in a first-degree relative (P < 0.025), and prior alcohol rehabilitation experience (P < 0.05) but not with a prior psychiatric history or less than 6 months of pretransplant sobriety. The authors indicate that prospective monitoring, using a combination of methods, is the most accurate approach to identify alcohol consumption. With this type of accuracy, risk factors can be identified and alcohol use can be compared with alcohol-related morbidity posttransplant.

Relation between plasma ascorbic acid and mortality in men and women in EPIC-Norfolk prospective study: a prospective population study. European Prospective Investigation into Cancer and Nutrition

BACKGROUND

Ascorbic acid (vitamin C) might be protective for several chronic diseases. However, findings from prospective studies that relate ascorbic acid to cardiovascular disease or cancer are not consistent. We aimed to assess the relation between plasma ascorbic acid and subsequent mortality due to all causes, cardiovascular disease, ischaemic heart disease, and cancer.

METHODS

We prospectively examined for 4 years the relation between plasma ascorbic acid concentrations and mortality due to all causes, and to cardiovascular disease, ischaemic heart disease, and cancer in 19 496 men and women aged 45-79 years. We recruited individuals by post using age-sex registers of general practices. Participants completed a health and lifestyle questionnaire and were examined at a clinic visit. They were followed-up for causes of death for about 4 years. Individuals were divided into sex-specific quintiles of plasma ascorbic acid. We used the Cox proportional hazard model to determine the effect of ascorbic acid and other risk factors on mortality.

FINDINGS

Plasma ascorbic acid concentration was inversely related to mortality from all-causes, and from cardiovascular disease, and ischaemic heart disease in men and women. Risk of mortality in the top ascorbic acid quintile was about half the risk in the lowest quintile (p<0.0001). The relation with mortality was continuous through the whole distribution of ascorbic acid concentrations. 20 micromol/L rise in plasma ascorbic acid concentration, equivalent to about 50 g per day increase in fruit and vegetable intake, was associated with about a 20% reduction in risk of all-cause mortality (p<0.0001), independent of age, systolic blood pressure, blood cholesterol, cigarette smoking habit, diabetes, and supplement use. Ascorbic acid was inversely related to cancer mortality in men but not women.

INTERPRETATION

Small increases in fruit and vegetable intake of about one serving daily has encouraging prospects for possible prevention of disease.

Predicted long-term mortality reduction associated with the second round of breast screening in East Anglia

Randomized trials have demonstrated that mammographic screening can reduce breast cancer mortality. Our aim was to estimate the reduction in mortality expected from the East Anglian Breast Screening Programme. Breast screening achieves benefit by improving cancer prognosis (reducing tumour size, nodal involvement and possibly grade) through earlier diagnosis. We compared cancer prognosis between women invited for screening and those not yet invited in East Anglia, UK, in order to predict the mortality reduction achievable by screening, independently of any reduction due to changes in treatment and underlying disease. Participants (both invited and not-yet invited) were women eligible for invitation to first and second screens and diagnosed with invasive breast cancer in 1989-96. Death rates were predicted based on the observed distribution of tumour grade, size and node status amongst 950 cancers diagnosed following first invitation, up to and including at second screen (excluding those detected at first screening), and 451 cancers presenting symptomatically in women awaiting first invitation during the staggered introduction of screening, after adjustment for lead time amongst screen detected cases. For all ages, the ratio of predicted breast cancer mortality in the invited compared with the uninvited group was 0.85 (95% CI 0.78, 0.93). It was 0.93 (0.80, 1.08) for women aged 50-54 at diagnosis and 0.81 (0.72, 0.91) for those aged 55-64. We conclude that, by 2004, the second round of screening in East Anglia should reduce mortality by around 7% in women below age 55 at diagnosis, and by around 19% in those aged 55-64.

Glycated haemoglobin, diabetes, and mortality in men in Norfolk cohort of european prospective investigation of cancer and nutrition (EPIC-Norfolk)

OBJECTIVE

To examine the value of glycated haemoglobin (HbA(1c)) concentration, a marker of blood glucose concentration, as a predictor of death from cardiovascular and all causes in men.

DESIGN

Prospective population study.

SETTING

Norfolk cohort of European Prospective Investigation into Cancer and Nutrition (EPIC-Norfolk).

SUBJECTS

4662 men aged 45-79 years who had had glycated haemoglobin measured at the baseline survey in 1995-7 who were followed up to December 1999.

MAIN OUTCOME MEASURES

Mortality from all causes, cardiovascular disease, ischaemic heart disease, and other causes.

RESULTS

Men with known diabetes had increased mortality from all causes, cardiovascular disease, and ischaemic disease (relative risks 2.2, 3.3, and 4.2, respectively, P <0.001 independent of age and other risk factors) compared with men without known diabetes. The increased risk of death among men with diabetes was largely explained by HbA(1c) concentration. HbA(1c) was continuously related to subsequent all cause, cardiovascular, and ischaemic heart disease mortality through the whole population distribution, with lowest rates in those with HbA(1c) concentrations below 5%. An increase of 1% in HbA(1c) was associated with a 28% (P<0.002) increase in risk of death independent of age, blood pressure, serum cholesterol, body mass index, and cigarette smoking habit; this effect remained (relative risk 1.46, P=0.05 adjusted for age and risk factors) after men with known diabetes, a HbA(1c) concentration >/=7%, or history of myocardial infarction or stroke were excluded. 18% of the population excess mortality risk associated with a HbA(1c) concentration >/=5% occurred in men with diabetes, but 82% occurred in men with concentrations of 5%-6.9% (the majority of the population).

CONCLUSIONS

Glycated haemoglobin concentration seems to explain most of the excess mortality risk of diabetes in men and to be a continuous risk factor through the whole population distribution. Preventive efforts need to consider not just those with established diabetes but whether it is possible to reduce the population distribution of HbA(1c) through behavioural means.

Mannosylerythritol lipid induces characteristics of neuronal differentiation in PC12 cells through an ERK-related signal cascade

Rat pheochromocytoma PC12 cells undergo neuronal differentiation in response to nerve growth factor (NGF). The differentiation involves protein kinase cascades that include the kinases MEK and ERK, as well as activation of the transcription factors c-Jun and c-Fos. We show here, that exposure of PC12 cells to mannosylerythritol lipid (MEL), a yeast extracellular glycolipid, enhances the activity of acetylcholinesterase and interrupts the cell cycle at the G1 phase, with resulting outgrowth of neurites and partial cellular differentiation. Treatment with MEL stimulates the phosphorylation of ERK to a similar extent as treatment with NGF, although, the appearance of phosphorylated ERK is somewhat delayed. Both the MEL-induced outgrowth of neurites and the increase in the activity of acetylcholinesterase are prevented by PD98059, a specific inhibitor of MEK. Northern blotting analysis of c-jun transcripts and analysis of transcription in PC12 cells of a c-jun/CAT reporter construct demonstrated a significant increase in the rate of transcription of the c-jun gene upon treatment with MEL. The sequence elements required for the MEL-mediated activation of transcription of the c-jun gene are located between nucleotides -126 and -79 in the 5' flanking region. Our results suggest that MEL induces characteristics of neuronal differentiation in PC12 cells, with transactivation of the c-jun gene, via an ERK-related signal cascade that is partially overlapping the pathways activated in response to NGF. These results might provide the groundwork for the use of microbial extracellular glycolipids as novel reagents for the treatment of cancer cells.

Alcohol use following liver transplantation: a comparison of follow-up methods

Alcoholic cirrhosis is one of the most common indications for liver transplantation. Previous researchers have studied rates of return to drinking following transplantation, however, few have employed prospective measures of alcohol use. The authors prospectively studied the alcohol use of patients transplanted for alcoholic liver disease. The authors improved the accuracy of monitoring alcohol use by using various methods for tracking patient's alcohol consumption, and we report on the time to first alcohol use after transplantation comparing these different methods. The authors found that alcohol use can occur very early after transplantation, even within the first 3 months posttransplant. Thirty-eight percent of the patients consumed any alcohol after transplantation. The clinical interviews by the psychiatrist were the most successful method for identifying posttransplant alcohol use. Posttransplant alcohol use was significantly associated with prior nonalcohol substance use (P < 0.025), family history of alcoholism in a first-degree relative (P < 0.025), and prior alcohol rehabilitation experience (P < 0.05) but not with a prior psychiatric history or less than 6 months of pretransplant sobriety. The authors indicate that prospective monitoring, using a combination of methods, is the most accurate approach to identify alcohol consumption. With this type of accuracy, risk factors can be identified and alcohol use can be compared with alcohol-related morbidity posttransplant.

A pooled analysis of magnetic fields and childhood leukaemia

Previous studies have suggested an association between exposure to 50-60 Hz magnetic fields (EMF) and childhood leukaemia. We conducted a pooled analysis based on individual records from nine studies, including the most recent ones. Studies with 24/48-hour magnetic field measurements or calculated magnetic fields were included. We specified which data analyses we planned to do and how to do them before we commenced the work. The use of individual records allowed us to use the same exposure definitions, and the large numbers of subjects enabled more precise estimation of risks at high exposure levels. For the 3203 children with leukaemia and 10 338 control children with estimated residential magnetic field exposures levels < 0.4 microT, we observed risk estimates near the no effect level, while for the 44 children with leukaemia and 62 control children with estimated residential magnetic field exposures >/= 0.4 microT the estimated summary relative risk was 2.00 (1.27-3.13), P value = 0.002). Adjustment for potential confounding variables did not appreciably change the results. For North American subjects whose residences were in the highest wire code category, the estimated summary relative risk was 1.24 (0.82-1.87). Thus, we found no evidence in the combined data for the existence of the so-called wire-code paradox. In summary, the 99.2% of children residing in homes with exposure levels < 0.4 microT had estimates compatible with no increased risk, while the 0.8% of children with exposures >/= 0.4 microT had a relative risk estimate of approximately 2, which is unlikely to be due to random variability. The explanation for the elevated risk is unknown, but selection bias may have accounted for some of the increase.

High-risk mammographic parenchymal patterns, hormone replacement therapy and other risk factors: a case-control study

BACKGROUND

Mammographic parenchymal patterns are of particular interest because the denser patterns reduce screening sensitivity as well as increasing breast cancer risk, and because they have been shown to be affected by exogenous oestrogens.

METHODS

We designed a case-control study comprising 200 cases with high-risk (P2 and DY) pattern and 200 controls with low-risk (N1 and P1) pattern. Mammograms were evaluated according to the Wolfe classification.

RESULTS

Parity, body mass index (BMI) and current smoking were inversely and independently associated, whereas late age of menarche and history of benign breast disease were positively associated with high-risk mammographic patterns. Current-users of hormone replacement therapy (HRT) were more than twice as likely to have a high-risk pattern than never-users (OR = 2.48, 95% CI : 1.32-4.61). Women who used HRT for more than 5 years were almost three times more likely to have a high-risk pattern than never-users (OR = 2.77, 95% CI : 1.11-6.91). Relative to never-users, women who started HRT before the menopause were more than twice as likely to have a high-risk pattern (OR = 2.53, 95% CI : 1.31-4.87).

CONCLUSIONS

Careful clinical and mammographical follow-up might be appropriate in women undergoing HRT. The HRT-induced mammographic pattern might be regarded as a new baseline and changes with respect to this new pattern could then be monitored over time.