Cystatin B-deficiency triggers ectopic histone H3 tail cleavage during neurogenesis.

Cystatin B (CSTB) acts as an inhibitor of cysteine proteases of the cathepsin family and loss-of-function mutations result in human brain diseases with a genotype-phenotype correlation. In the most severe case, CSTB-deficiency disrupts brain development, and yet the molecular basis of this mechanism is missing. Here, we establish CSTB as a regulator of chromatin structure during neural stem cell renewal and differentiation. Murine neural precursor cells (NPCs) undergo transient proteolytic cleavage of the N-terminal histone H3 tail by cathepsins B and L upon induction of differentiation into neurons and glia. In contrast, CSTB-deficiency triggers premature H3 tail cleavage in undifferentiated self-renewing NPCs and sustained H3 tail proteolysis in differentiating neural cells. This leads to significant transcriptional changes in NPCs, particularly of nuclear-encoded mitochondrial genes. In turn, these transcriptional alterations impair the enhanced mitochondrial respiration that is induced upon neural stem cell differentiation. Collectively, our findings reveal the basis of epigenetic regulation in the molecular pathogenesis of CSTB deficiency.

Musculoskeletal symptoms and computer use among Finnish adolescents--pain intensity and inconvenience to everyday life: a cross-sectional study.

BACKGROUND: Musculoskeletal symptoms among adolescents are related to the time spent using a computer, but little is known about the seriousness of the symptoms or how much they affect everyday life. The purpose of the present study was to examine the intensity of musculoskeletal pain and level of inconvenience to everyday life, in relation to time spent using a computer. METHODS: In a survey, 436 school children (12 to 13 and 15 to 16 years of age), answered a questionnaire on musculoskeletal and computer-associated musculoskeletal symptoms in neck-shoulder, low back, head, eyes, hands, and fingers or wrists. Pain intensity (computer-associated symptoms) and inconvenience to everyday life (musculoskeletal symptoms) were measured using a visual analogue scale. Based on the frequency and intensity, three categories were formed to classify pain at each anatomic site: none, mild, and moderate/severe. The association with time spent using the computer was analyzed by multinomial logistic regression. RESULTS: Moderate/severe pain intensity was most often reported in the neck-shoulders (21%); head (20%); and eyes (14%); and moderate/severe inconvenience to everyday life was most often reported due to head (29%), neck-shoulders (21%), and low back (16%) pain. Compared with those using the computer less than 3.6 hours/week, computer use of ≥ 14 hours/week, was associated with moderate/severe increase in computer-associated musculoskeletal pain at all anatomic sites (odds ratio [OR] = 2.9-4.4), and moderate/severe inconvenience to everyday life due to low back (OR = 2.5) and head (OR = 2.0) pain. CONCLUSIONS: Musculoskeletal symptoms causing moderate/severe pain and inconvenience to everyday life are common among adolescent computer users. Daily computer use of 2 hours or more increases the risk for pain at most anatomic sites.

Clustered metabolic risk and leisure-time physical activity in adolescents: effect of dose?

OBJECTIVES: The authors studied the association of leisure-time physical activity (LTPA) with clustered and individual metabolic risk factors in adolescents taking into account diet and pubertal status. The authors also studied whether screen time was associated with clustered risk. METHODS: Self-reported LTPA and screen time, lipids, lipoproteins, apolipoproteins, high-sensitivity C reactive protein, blood pressure, body mass index (BMI), pubertal status and diet were assessed in 13-year-old adolescents (n=542) participating in an atherosclerosis prevention study (Special Turku Coronary Risk Factor Intervention Project for Children). Activity groups were formed according to sex-specific LTPA index tertile cut-off points. BMI, high-density lipoprotein cholesterol (HDL-C), triglycerides and blood pressure comprised the cluster. RESULTS: An increase in LTPA was associated with a decreased risk for clustered metabolic risk in girls. When sedentary and highly active adolescents were compared, an increase in LTPA decreased clustering of risk factors in boys as well. Little extra benefit on clustered risk was obtained by increasing LTPA from 30 MET h/week (eg, 4-5 h/week bicycling or playing soccer) to 50 MET h/week (eg, 7-8 h/week bicycling or playing soccer). LTPA was beneficially associated with BMI, HDL-C, systolic blood pressure and HDL-C/total cholesterol in girls and HDL-C in boys. Diet and pubertal status were similar in all activity groups. In girls, screen time >2 h/day was associated with an increased risk for clustered risk, independent of LTPA. CONCLUSION: Sedentary adolescents had an increased risk for clustered metabolic risk compared with physically more active peers. Only minor extra benefit was obtained when LTPA increased over 30 MET h/week. Focus in the prevention of clustered risk should especially be on avoiding sedentary lifestyle.

Cystatin B deficiency results in sustained histone H3 tail cleavage in postnatal mouse brain mediated by increased chromatin-associated cathepsin L activity.

Cystatin B (CSTB) is a cysteine cathepsin inhibitor whose biallelic loss-of-function mutations in human result in defects in brain development and in neurodegeneration. The physiological function of CSTB is largely unknown, and the mechanisms underlying the human brain diseases remain poorly understood. We previously showed that CSTB modulates the proteolysis of the N-terminal tail of histone H3 (H3cs1) during in vitro neurogenesis. Here we investigated the significance of this mechanism in postnatal mouse brain. Spatiotemporal analysis of H3cs1 intensity showed that while H3cs1 in wild-type (wt) mice was found at varying levels during the first postnatal month, it was virtually absent in adult brain. We further showed that the high level of H3cs1 coincides with chromatin association of de novo synthesized cathepsin L suggesting a role for nuclear cathepsin L in brain development and maturation. On the contrary, the brains of Cstb -/- mice showed sustained H3cs1 proteolysis to adulthood with increased chromatin-associated cathepsin L activity, implying that CSTB regulates chromatin-associated cathepsin L activity in the postnatal mouse brain. As H3 tail proteolysis has been linked to cellular senescence in vitro, we explored the presence of several cellular senescence markers in the maturing Cstb -/- cerebellum, where we see increased levels of H3cs1. While several markers showed alterations in Cstb -/- mice, the results remained inconclusive regarding the association of deficient CSTB function with H3cs1-induced senescence. Together, we identify a molecular role for CSTB in brain with implications for brain development and disease.

Cystatin B deficiency sensitizes neurons to oxidative stress in progressive myoclonus epilepsy, EPM1.

The progressive myoclonus epilepsies, featuring the triad of myoclonus, seizures, and ataxia, comprise a large group of inherited neurodegenerative diseases that remain poorly understood and refractory to treatment. The Cystatin B gene is mutated in one of the most common forms of progressive myoclonus epilepsy, Unverricht-Lundborg disease (EPM1). Cystatin B knockout in a mouse model of EPM1 triggers progressive degeneration of cerebellar granule neurons. Here, we report impaired redox homeostasis as a key mechanism by which Cystatin B deficiency triggers neurodegeneration. Oxidative stress induces the expression of Cystatin B in cerebellar granule neurons, and EPM1 patient-linked mutation of the Cystatin B gene promoter impairs oxidative stress induction of Cystatin B transcription. Importantly, Cystatin B knockout or knockdown sensitizes cerebellar granule neurons to oxidative stress-induced cell death. The Cystatin B deficiency-induced predisposition to oxidative stress in neurons is mediated by the lysosomal protease Cathepsin B. We uncover evidence of oxidative damage, reflected by depletion of antioxidants and increased lipid peroxidation, in the cerebellum of Cystatin B knock-out mice in vivo. Collectively, our findings define a pathophysiological mechanism in EPM1, whereby Cystatin B deficiency couples oxidative stress to neuronal death and degeneration, and may thus provide the basis for novel treatment approaches for the progressive myoclonus epilepsies.

Computer-associated health complaints and sources of ergonomic instructions in computer-related issues among Finnish adolescents: a cross-sectional study.

BACKGROUND: The use of computers has increased among adolescents, as have musculoskeletal symptoms. There is evidence that these symptoms can be reduced through an ergonomics approach and through education. The purpose of this study was to examine where adolescents had received ergonomic instructions related to computer use, and whether receiving these instructions was associated with a reduced prevalence of computer-associated health complaints. METHODS: Mailed survey with nationally representative sample of 12 to 18-year-old Finns in 2001 (n = 7292, response rate 70%). In total, 6961 youths reported using a computer. We tested the associations of computer use time and received ergonomic instructions (predictor variables) with computer-associated health complaints (outcome variables) using logistic regression analysis. RESULTS: To prevent computer-associated complaints, 61.2% reported having been instructed to arrange their desk/chair/screen in the right position, 71.5% to take rest breaks. The older age group (16-18 years) reported receiving instructions or being self-instructed more often than the 12- to 14-year-olds (p < 0.001). Among both age groups the sources of instructions included school (33.1%), family (28.6%), self (self-instructed) (12.5%), ICT-related (8.6%), friends (1.5%) and health professionals (0.8%). Receiving instructions was not related to lower prevalence of computer-associated health complaints. CONCLUSIONS: This report shows that ergonomic instructions on how to prevent computer-related musculoskeletal problems fail to reach a substantial number of children. Furthermore, the reported sources of instructions vary greatly in terms of reliability.

Vascular endothelial function and leisure-time physical activity in adolescents.

BACKGROUND: Exercise training improves endothelial function in high-risk adolescents, but the influence of habitual leisure-time physical activity on endothelial function in healthy adolescents is unknown. METHODS AND RESULTS: Brachial artery flow-mediated endothelial function and physical activity habits were assessed in 483 adolescents (13 years of age) participating in an atherosclerosis prevention study (Special Turku Coronary Risk Factor Intervention Project for Children [STRIP]). Endothelial function was examined with ultrasound; physical activity was assessed with self-administered questionnaires. A leisure-time physical activity index was calculated by multiplying mean weekly leisure-time exercise intensity, duration, and frequency [boys, 31.2 +/- 23.0 MET h/wk (mean +/- SD); girls, 24.0 +/- 20.9 MET h/wk; P for gender difference=0.0003]. Maximum flow-mediated dilatation (FMD) and total FMD response (the area under the dilatation curve 40 to 180 seconds after hyperemia) were calculated. In boys, maximum FMD and area under the dilatation curve 40 to 180 seconds after hyperemia were directly associated with leisure-time physical activity index in regression analyses adjusted for brachial artery diameter (maximum FMD, P=0.020; area under the dilatation curve 40 to 180 seconds after hyperemia, P=0.0055). These associations remained significant after further adjustments for body mass index, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, high-sensitivity C-reactive protein, and systolic blood pressure. A difference of approximately 50 MET h/wk corresponding to approximately 10 hours of moderate intensity activity weekly between sedentary and active boys was associated with an approximately 1% unit difference in maximum FMD. CONCLUSIONS: Leisure-time physical activity is directly associated with brachial artery FMD responses in 13-year-old boys, providing evidence that physical activity beneficially influences endothelial function in healthy male adolescents. Lack of association in girls may reflect their overall lower physical activity level.

Cystatin B: mutation detection, alternative splicing and expression in progressive myclonus epilepsy of Unverricht-Lundborg type (EPM1) patients.

Progressive myoclonus epilepsy of Unverricht-Lundborg type (EPM1) is an autosomal recessive neurodegenerative disorder caused by mutations in the cystatin B gene (CSTB) that encodes an inhibitor of several lysosomal cathepsins. An unstable expansion of a dodecamer repeat in the CSTB promoter accounts for the majority of EPM1 disease alleles worldwide. We here describe a novel PCR protocol for detection of the dodecamer repeat expansion. We describe two novel EPM1-associated mutations, c.149G > A leading to the p.G50E missense change and an intronic 18-bp deletion (c.168+1_18del), which affects splicing of CSTB. The p.G50E mutation that affects the conserved QVVAG amino acid sequence critical for cathepsin binding fails to associate with lysosomes. This further supports the previously implicated physiological importance of the CSTB-lysosome association. Expression of CSTB mRNA and protein was markedly reduced in lymphoblastoid cells of the patients irrespective of the mutation type. Patients homozygous for the dodecamer expansion mutation showed 5-10% expression compared to controls. By combining database searches with RT-PCR we identified several alternatively spliced CSTB isoforms. One of these, CSTB2, was also present in mouse and was analyzed in more detail. In real-time PCR quantification, CSTB2 expression was less than 5% of total CSTB expression in all human adult and fetal tissues analyzed. In patients homozygous for the minisatellite mutation, the level of CSTB2 was reduced similarly to that of CSTB implicating regulation from the same promoter. The physiological significance of CSTB2 remains to be determined.

Gene-Expression Profiling Suggests Impaired Signaling via the Interferon Pathway in Cstb-/- Microglia.

Progressive myoclonus epilepsy of Unverricht-Lundborg type (EPM1, OMIM254800) is an autosomal recessive neurodegenerative disorder characterized by stimulus-sensitive and action-activated myoclonus, tonic-clonic epileptic seizures, and ataxia. Loss-of-function mutations in the gene encoding the cysteine protease inhibitor cystatin B (CSTB) underlie EPM1. The deficiency of CSTB in mice (Cstb-/- mice) generates a phenotype resembling the symptoms of EPM1 patients and is accompanied by microglial activation at two weeks of age and an upregulation of immune system-associated genes in the cerebellum at one month of age. To shed light on molecular pathways and processes linked to CSTB deficiency in microglia we characterized the transcriptome of cultured Cstb-/- mouse microglia using microarray hybridization and RNA sequencing (RNA-seq). The gene expression profiles obtained with these two techniques were in good accordance and not polarized to either pro- or anti-inflammatory status. In Cstb-/- microglia, altogether 184 genes were differentially expressed. Of these, 33 genes were identified by both methods. Several interferon-regulated genes were weaker expressed in Cstb-/- microglia compared to control. This was confirmed by quantitative real-time PCR of the transcripts Irf7 and Stat1. Subsequently, we explored the biological context of CSTB deficiency in microglia more deeply by functional enrichment and canonical pathway analysis. This uncovered a potential role for CSTB in chemotaxis, antigen-presentation, and in immune- and defense response-associated processes by altering JAK-STAT pathway signaling. These data support and expand the previously suggested involvement of inflammatory processes to the disease pathogenesis of EPM1 and connect CSTB deficiency in microglia to altered expression of interferon-regulated genes.

Dietary fat predicts coronary heart disease events in subjects with type 2 diabetes.

OBJECTIVE: To investigate whether quantity or quality of dietary fat predicts coronary heart disease (CHD) events in middle-aged type 2 diabetic subjects. RESEARCH DESIGN AND METHODS: The dietary habits of 366 type 2 diabetic men and 295 women, aged 45-64 years and free from CHD, were assessed with a 53-item food frequency questionnaire. They were followed up for 7 years. RESULTS: Men in the highest tertile of the polyunsaturated/saturated fat (P/S) ratio (>0.28) had a significantly lower risk for CHD death than men in the two lowest tertiles (5.0 vs. 14.2%, P = 0.009). The risk for all CHD events was 14.2 vs. 23.2%, respectively (P = 0.044). P/S ratio did not predict CHD events in women. In Cox multiple regression analyses taking into account other cardiovascular risk factors, the highest P/S ratio tertile was associated with the lowest rate of CHD death in men (P = 0.048). CONCLUSIONS: Low P/S ratio in men predicted future CHD events in type 2 diabetic subjects independently of conventional CHD risk factors.

Gene expression alterations in the cerebellum and granule neurons of Cstb(-/-) mouse are associated with early synaptic changes and inflammation.

Progressive myoclonus epilepsy of Unverricht-Lundborg type (EPM1) is an autosomal recessively inherited neurodegenerative disease, manifesting with myoclonus, seizures and ataxia, caused by mutations in the cystatin B (CSTB) gene. With the aim of understanding the molecular basis of pathogenetic events in EPM1 we characterized gene expression changes in the cerebella of pre-symptomatic postnatal day 7 (P7) and symptomatic P30 cystatin B -deficient (Cstb(-/-) ) mice, a model for the disease, and in cultured Cstb(-/-) cerebellar granule cells using a pathway-based approach. Differentially expressed genes in P7 cerebella were connected to synaptic function and plasticity, and in cultured cerebellar granule cells, to cell cycle, cytoskeleton, and intracellular transport. In particular, the gene expression data pinpointed alterations in GABAergic pathway. Electrophysiological recordings from Cstb(-/-) cerebellar Purkinje cells revealed a shift of the balance towards decreased inhibition, yet the amount of inhibitory interneurons was not declined in young animals. Instead, we found diminished number of GABAergic terminals and reduced ligand binding to GABAA receptors in Cstb(-/-) cerebellum. These results suggest that alterations in GABAergic signaling could result in reduced inhibition in Cstb(-/-) cerebellum leading to the hyperexcitable phenotype of Cstb(-/-) mice. At P30, the microarray data revealed a marked upregulation of immune and defense response genes, compatible with the previously reported early glial activation that precedes neuronal degeneration. This further implies the role of early-onset neuroinflammation in the pathogenesis of EPM1.

Eating behavior influences diet, weight, and central obesity in women after pregnancy.

OBJECTIVE: The aim of this study was to explore whether type of eating behavior is related to diet and overweight in women after childbirth. METHODS: In a prospective mother-infant study, women's (N = 189) eating behavior, dietary intake from food diaries, weight, and waist circumference (WC) were measured at 6, 12, 24, and 48 mo after giving birth. Three aspects of eating behavior were measured by the validated Three Factor Eating Questionnaire-18: cognitive restraint (CR; restricting of eating without associated hunger or fullness), emotional eating (EE; overeating due to negative feelings), and uncontrolled eating (UE; overeating irrespective of physiologic need). RESULTS: High scores in CR associated with the lowest tertile of fat intake (% of energy [E%], P = 0.045). High UE scores associated with the highest tertiles of intakes of energy (kcal; P < 0.001), fiber (g; P < 0.001) and sucrose (E%; P < 0.001). High EE scores (P = 0.003) linked with overweight (body mass index ≥ 25 kg/m(2)), whereas UE (P < 0.001) linked with central obesity (WC ≥ 80 cm). CONCLUSIONS: We demonstrated that certain types of eating behavior related to both energy-dense diet and weight and central adiposity. We propose that measuring eating behavior by the simple questionnaire could be a helpful tool in dietary counseling that aids in identifying women who are likely at risk for unhealthy dietary patterns and for developing overweight.

Bioavailability of quercetin from berries and the diet.

Berries are a rich source of various polyphenols, including the flavonoid quercetin. In this article, the results of three intervention studies investigating the bioavailability of quercetin from berries are reviewed. In the first study, we investigated the short-term kinetics of quercetin after consumption of black currant juice and showed that quercetin is rapidly absorbed from it. In the second study, we showed that plasma quercetin levels increase up to 50% in subjects consuming 100 g/day of bilberries, black currants, and lingonberries as a part of their normal diets for 2 mo. In the third study, healthy subjects consumed a diet high or low in vegetables, berries, and other fruit for 6 wk. Quercetin concentrations nearly doubled in the high-vegetable, -berry, and -other fruit group and decreased by 30% in subjects consuming less of these foods than normally. The results showed that plasma quercetin is bioavailable from a diet containing berries and indicate that it may be a good biomarker of fruit and vegetable intake in general.

Frequent computer-related activities increase the risk of neck-shoulder and low back pain in adolescents.

BACKGROUND: Neck-shoulder pain (NSP) and low back pain (LBP) increased among adolescents in the 1990s and the beginning of 2000. A potential risk factor for this increase is the use of information and communication technology. We studied how the use of computers, the Internet, and mobile phones, playing digital games and viewing television are related to NSP and LBP in adolescents. METHODS: Mailed survey with nationally representative samples of 14-, 16-, and 18-year-old Finns in 2003 (n = 6003, response rate 68%). The outcome variables were weekly NSP and LBP. RESULTS: NSP was perceived by 26% and LBP by 12%. When compared with non-users, the risk of NSP was 1.3 (adjusted odds ratios) when using computers > 2-3 h/day, and 1.8 when using 4-5 h/day; 2.5 when using computers > or = 42 h/week, and 1.7 when using the Internet > or = 42 h/week. Compared with non-users, the risk of LBP was 2.0 when using computers > 5 h/day, 1.7 when using > or = 42 h/week, 1.8 when using the Internet > or = 42 h/week, and 2.0 when playing digital games > 5 h/day. Times spent on digital gaming, viewing television, and using mobile phones were not associated with NSP, nor were use of mobile phones and viewing television with LBP after adjusting for confounding factors. CONCLUSIONS: Frequent computer-related activities are an independent risk factor for NSP and LBP. Daily use of computers exceeding 2-3 h seems to be a threshold for NSP and exceeding 5 h for LBP. Computer-related activities may explain the increase of NSP and LBP in the 1990s and the beginning of 2000.

Dietary and serum vitamins and minerals as predictors of myocardial infarction and stroke in elderly subjects.

BACKGROUND AND AIM: According to a widespread hypothesis, antioxidative vitamins and trace elements may protect the body against atherosclerotic diseases, especially in the elderly. We assessed dietary and serum vitamins and minerals for prediction of acute myocardial infarction (AMI) and stroke in elderly subjects. METHODS AND RESULTS: In a population-based health survey with special emphasis on the diet, subjects aged 65-99 years were followed up for up to 10 years. The study population consisted of 361 men and 394 women. Information on individual food consumption was elicited by means of dietary history interviews. Serum vitamins and mineral elements were analysed utilizing commonly applied biochemical methods. Prediction analyses were based on 130 cases accumulated in the AMI group, 70 subjects in the stroke group, and corresponding control subjects. The cases were determined on the basis of revised information from the National Register of Cases of Death, and from the National Hospital Discharge Register. Low intake of vitamin D (p = 0.011) and low serum levels of 1,25-dihydroxy-vitamin D (p = 0.0053) were significantly predictive of stroke when adjusted for age, gender, smoking and functional capacity. On the other hand, high dietary intakes of two flavonoids, luteolin (p = 0.0096) and kaempferol (p = 0.002) were associated with lowered risk of AMI. Furthermore, low serum levels of iron predicted both AMI (p = 0.013) and stroke (p = 0.019). The results remained essentially unchanged when adjusted for additional major risk factors of atherosclerosis. CONCLUSIONS: From the items in the dietary interview, low intakes of vitamin D and certain flavonoids emerged as the sole predictors of AMI and stroke. In biochemical analyses, on the other hand, these disorders were predicted only by low levels of 1,25-dihydroxy-vitamin D and iron in the serum.

Back, neck, and shoulder pain in Finnish adolescents: national cross sectional surveys.

OBJECTIVES: To study changes in pain of the back and neck in adolescents between 1985 and 2001 and pain of the neck, shoulder, and lower back between 1991 and 2001. DESIGN: Biennial nationwide postal surveys, 1985-2001, and annual classroom surveys, 1996-2001. SETTING: Finland. PARTICIPANTS: 62 677 12, 14, 16, and 18 year olds and 127 217 14-16 year olds. MAIN OUTCOME MEASURES: Pain in the back and neck, neck and shoulder, or lower back, at least weekly. RESULTS: Prevalence of pain in the back and neck was greater in the 1990s than in the 1980s and increased steadily from 1993 to 1997. Pain of the neck and shoulder and pain of the lower back was much more common in 1999 than in 1991 and in 2001 than in 1999. Pain was more common among girls and older groups: pain of the neck and shoulder affected 24% of girls and 12% of boys in 14 year olds, 38% of girls and 16% of boys in 16 year olds, and 45% of girls and 19% of boys in 18 year olds; pain in the lower back affected 8% of girls and 7% of boys in 14 year olds, 14% of girls and 11% of boys in 16 year olds, and 17% of boys and 13% of girls in 18 year olds. CONCLUSION: Pain in the neck, shoulder, and lower back is becoming more common in Finnish adolescents. This pain suggests a new disease burden of degenerative musculoskeletal disorders in future adults.

Assessment of alcohol consumption by mailed questionnaire in epidemiological studies: evaluation of misclassification using a dietary history interview and biochemical markers.

BACKGROUND: Self-reported information on alcohol from questionnaires is generally assumed to introduce misclassification of consumption, mainly in the direction of underestimation. The aim of this study was to evaluate self-reported information on alcohol consumption from a mailed questionnaire by comparing to a dietary history interview and biochemical markers of alcohol intake. SUBJECTS AND METHODS: For 76 male twin pairs of the Finnish Twin Cohort Study aged 40-70 years information on self-reported alcohol consumption was collected through mailed questionnaire and dietary history interview. Carbohydrate-deficient transferrin (CDT), Gamma-glutamyltransferase (Gamma-GT) and mean corpuscular volume (MCV) were determined from blood samples. RESULTS: Mean levels of CDT, gamma-GT and MCV showed a rise with increased self-reported alcohol consumption already at low levels of reported consumption (<20 g alcohol/day). There was a positive correlation between reported amount alcohol intake per day and levels of CDT (r = 0.46), gamma-GT (r = 0.32) and MCV (r = 0.36) but within the high consumption group (> or = 30 g/day) there was no such correlation. The questionnaire had sensitivity of 28-43% and specificity of 89% for identification of high consumers of alcohol using the biochemical markers as reference and sensitivity 41% and specificity 94% using the dietary history interview as reference. Sensitivity was improved when information on binge drinking (82%) or possible drinking problems (73%) was considered. CONCLUSION: Comparison to dietary history interview as well as to biochemical markers indicate that self-reported information on alcohol consumption from a mailed questionnaire may be used to distinguish between groups with different levels of alcohol consumption. The suggested misclassification of high consumers implies that only strong associations between high alcohol intake and disease are likely to be detected in studies based on questionnaire data.