International Lung Cancer Consortium: pooled analysis of sequence variants in DNA repair and cell cycle pathways

BACKGROUND

The International Lung Cancer Consortium was established in 2004. To clarify the role of DNA repair genes in lung cancer susceptibility, we conducted a pooled analysis of genetic variants in DNA repair pathways, whose associations have been investigated by at least 3 individual studies.

METHODS

Data from 14 studies were pooled for 18 sequence variants in 12 DNA repair genes, including APEX1, OGG1, XRCC1, XRCC2, XRCC3, ERCC1, XPD, XPF, XPG, XPA, MGMT, and TP53. The total number of subjects included in the analysis for each variant ranged from 2,073 to 13,955 subjects.

RESULTS

Four of the variants were found to be weakly associated with lung cancer risk with borderline significance: these were XRCC3 T241M [heterozygote odds ratio (OR), 0.89; 95% confidence interval (95% CI), 0.79-0.99 and homozygote OR, 0.84; 95% CI, 0.71-1.00] based on 3,467 cases and 5,021 controls from 8 studies, XPD K751Q (heterozygote OR, 0.99; 95% CI, 0.89-1.10 and homozygote OR, 1.19; 95% CI, 1.02-1.39) based on 6,463 cases and 6,603 controls from 9 studies, and TP53 R72P (heterozygote OR, 1.14; 95% CI, 1.00-1.29 and homozygote OR, 1.20; 95% CI, 1.02-1.42) based on 3,610 cases and 5,293 controls from 6 studies. OGG1 S326C homozygote was suggested to be associated with lung cancer risk in Caucasians (homozygote OR, 1.34; 95% CI, 1.01-1.79) based on 2,569 cases and 4,178 controls from 4 studies but not in Asians. The other 14 variants did not exhibit main effects on lung cancer risk.

DISCUSSION

In addition to data pooling, future priorities of International Lung Cancer Consortium include coordinated genotyping and multistage validation for ongoing genome-wide association studies.

Molecular epidemiology of major depressive disorder

Major depressive disorder causes significant morbidity, affecting people's ability to work, function in relationships, and engage in social activities. Moreover, major depressive disorder increases the risk of suicidal ideation, attempted suicide and death by completed suicide. There is evidence that chronic stress can cause major depressive disorder. As for genetic factors, only minor susceptibility genes have been reliably identified. The serotonin system provides a logical source of susceptibility genes for depression, because this system is the target of selective serotonin reuptake-inhibitor drugs that are effective in treating depression. The 5-hydroxytryptamine (serotonin) transporter (5-HTT) has received particular attention because it is involved in the reuptake of serotonin at brain synapses. One common polymorphic variant of the 5-HTT-linked polymorphic region (5-HTTLPR), which affects the promoter of the 5-HTT gene, causes reduced uptake of the neurotransmitter serotonin into the presynaptic cells in the brain. The authors discussed the relationship between genetic polymorphisms and major depressive disorder, with special emphasis on the 5-HTTTLPR polymorphism. As the 5-HTTLPR polymorphism was significantly associated with an increased risk of major depressive disorder, the 5-HTT gene may be a candidate for a major depressive disorder susceptibility gene. As major depressive disorder is a multifactorial disease, an improved understanding of the interplay of environmental and genetic polymorphisms at multiple loci may help identify individuals who are at increased risk for major depressive disorder. Hopefully, in the future we will be able to screen for major depressive disorder susceptibility by using specific biomarkers.

ADAM33 genetic polymorphisms and risk of atopic dermatitis among Japanese children

OBJECTIVES

ADAM33, a disintegrin and metalloproteinase 33, gene has been identified as an asthma susceptibility gene. The relationship between single nucleotide polymorphisms (SNPs) in ADAM33 and atopic dermatitis (AD) in Japanese children was examined using case-control design.

METHODS

Seven SNPs of ADAM33 (rs2853209, rs2787094, rs2280091, rs2280090, rs628977, rs597980, and rs528557) were analyzed in 140 AD cases and 258 controls aged 3 years.

RESULTS

Only rs2853209 (T>A) was significantly associated with AD risk. Sex-adjusted odds ratio (OR) for the AA versus the TT genotype was 0.55 (95% confidence interval (CI), 0.30-0.997). Consistent with the results of genotyping analysis, a haplotype carrying rs2853209 A allele was significantly associated with decreased risk of AD compared to all the other haplotypes combined (OR=0.26, 95% CI=0.08-0.69).

CONCLUSION

This is the first study to provide evidence for an association of the ADAM33 polymorphism with AD risk but the strength of this evidence is limited by our small sample size.

Breastfeeding and the risk of wheeze and asthma in Japanese infants: the Osaka Maternal and Child Health Study

Epidemiological evidence for an effect of breastfeeding on asthma continues to be inconclusive. The present prospective study examined the relationship between breastfeeding and the risk of wheeze and asthma in Japanese infants. A birth cohort of 763 infants was followed. The first survey during pregnancy and the second survey between 2 and 9 months postpartum collected information on potential confounding factors. Data on breastfeeding, wheeze, and asthma were obtained from questionnaires in the third survey from 16 to 24 months postpartum. Adjustment was made for maternal age, maternal and paternal history of asthma, atopic eczema, and allergic rhinitis, indoor domestic pets (cats, dogs, birds, or hamsters), family income, maternal and paternal education, maternal smoking during pregnancy, baby's sex, baby's older siblings, household smoking in the same room as the infant, and time of delivery before the third survey. By the third survey, the cumulative incidence of wheeze and asthma was 22.1% and 4.3%, respectively. Neither exclusive breastfeeding for 4 months or more nor partial breastfeeding for 6 months or more were materially related to the risk of wheeze. No measurable association was observed between exclusive breastfeeding for 4 months or more and the risk of asthma. Partial breastfeeding for 6 months or more was inversely related to the risk of asthma although the adjusted odds ratio (OR) was not statistically significant. When infants were stratified according to whether there was a negative or positive allergic history in at least 1 parent, a nearly 40% and 60% decrease, respectively, in the ORs were found for exclusive and partial breastfeeding only in infants without a parental allergic history, although the ORs were not statistically significant. The present prospective study showed no statistically significant relationship between breastfeeding duration and the risk of wheeze or asthma in Japanese infants.

Effect of genetic predisposition on the risk of gallbladder cancer in Hungary

A CYP1A1 polymorphism has been associated with an increased risk for gallbladder cancer (GBC) in Japanese women. However, genetic risk factors for GBC in Hungary, where the population has a relatively high GBC incidence, has not been well studied. We therefore tested associations between CYP1A1 T3801C, CYP1A1 Ile462Val, GSTM1deletion, and TP53 Arg72Pro and GBC in Hungary. Genomic DNA was extracted from peripheral blood of 100 controls (52 men and 48 women) and from the tissue embedded in paraffin of 43 cases (6 men and 37 women). The case-control analysis was limited to females due to a small number of males. Of 37 female cases, 21 (56.8%) were diagnosed as adenocarcinoma, and the remaining 16 (43.2%) were classified as non-adenocarcinoma. The odds ratios (ORs) for the Ile/Val genotype and the Val allele were 8.9 (95% CI: 2.9-27.4) and 4.4 (95% CI: 1.7-11.1), respectively. The occurrence of the combined variant genotypes of CYP1A1 Ile462Val and GSTM1 (37.8% vs. 8.3%) or CYP1A1 Ile462Val and TP53 Arg72Pro (24.3% vs. 0%) was significantly higher in the cases than in the controls. The Ile/Val genotype was significantly associated with an increased risk of adenocarcinoma (OR 9.2; 95% CI: 2.6-32.6) and non-adenocarcinoma (OR 8.4; 95% CI: 2.2-32.4). Additionally, the Arg/Pro genotype increased risk of non-adenocarcinoma (OR 3.8; 95% CI: 1.2-12.8). The Val allele may contribute to the development of GBC not only in Japanese but also in Hungarian women. Our results provide a rationale for further studies of genetic variation on the risk of GBC in Hungary.

Suicidal risk factors and completed suicide: meta-analyses based on psychological autopsy studies

The purpose of the present review is to evaluate the effects of common risk factors for suicide by meta-analyses using data extracted from studies based on the psychological autopsy method. We focused on five common risk factors of suicide: substance-related disorders, mood disorders, adverse marital status, adverse employment status, and self-harm behaviors. A total of 24 articles were identified from MEDLINE in which the crude odds ratio (OR) could be calculated for the above five risk factors through 30 April 2007, using such search keywords as "suicide," "psychological autopsy," and "case-control study." Overall, both substance-related disorders [OR = 5.24; 95% confidence interval (CI) = 3.30-8.31] and mood disorders [OR = 13.42; 95% CI = 8.05-22.37] were strongly associated with suicidal risk. Suicidal attempt and deliberate self-harm, which can directly lead to completed suicide, have been shown to be very strongly associated with suicidal risk [OR = 16.33; 95% CI = 7.51-35.52]. Effects of social factors such as adverse marital and employment status were relatively small. As substance-related disorders and mood disorders were strongly associated with an increased risk of completed suicide, the comorbidity of these two disorders should be paid a maximum attention. The effective prevention of suicide depends on whether we can successfully incorporate these personal factors as well as social factors into an adequate multi-factorial model.

A dose-escalation study of rituximab for treatment of systemic lupus erythematosus and Evans' syndrome: immunological analysis of B cells, T cells and cytokines

OBJECTIVE

Accumulating evidence suggests that B-cell depletion therapy by rituximab may be effective for autoimmune disorders. However, an optimal dose of rituximab and a mechanism of its action remain to be established. We performed a dose-escalation study for treatment of Japanese patients with autoimmune diseases including eight with SLE and one with Evans' syndrome.

METHODS

Rituximab was infused intravenously, weekly 4 times in a dose-escalating fashion at three different doses of 100, 250 or 375 mg/m(2) to three patients each. Immunological parameters were monitored at certain points until 12 months after the treatment.

RESULTS

Rituximab was well tolerated and safe in these patients. Seven out of eight SLE patients and one with Evans' syndrome clinically responded completely or partially to the treatment. Four patients achieved long-term remission (18-30 months) without any additional treatment. In these patients, a significant decrease in circulating B cells continued for 6 months after the treatment. The mean fluorescence intensities of CD19, CD21, CD40 and BR3 on the residual B cells as well as the percentage of CD69+ CD4+ T cells decreased significantly. Serum TNF-alpha levels decreased significantly on day 2. The Th1/Th2 balance of CD4+ T cells gradually shifted towards a Th1 type by 6 months.

CONCLUSION

In addition to B-cell depletion, modification of B-cell and T-cell phenotypes as well as cytokine profiles may be involved in the action of rituximab.

Factors related to starting and continuing smoking among senior high school boys in Fukuoka, Japan

The purpose of this study was to identify factors that influence starting and quitting smoking among Japanese male adolescents aged 15-18. Two thousand and twelve senior high school boys in Fukuoka City, Japan, answered unsigned self-administrated anonymous questionnaires in July 2001. Odds ratios (ORs) and their 95 % confidence intervals (CIs) were computed to assess the strength of associations between students' smoking status and alcohol consumption habits. Additionally, the link between a students' smoking status and parental influence (parental smoking) was also assessed. Approximately 90% of the students, both current and ex-smokers, had ever smoked prior to senior high school while 77% of the students (smokers and non-smokers) had the experience of drinking alcohol prior to admission to senior high school. After adjustment for school year (i.e., freshman, sophomore, junior, senior), academic education level, after-school club activities, time of first drinking experience and the frequency of drinking, there was a significant increased risk to become a smoker when one parent was a smoker (OR = 1.67, 95% CI = 1.18-2.37) or when both parents were smokers (OR = 2.94, 95% CI = 1.66-5.18) compared to both parents being non-smokers. The consumption of alcohol prior to entering senior high school was significantly associated with more than 2.5-fold greater risk for the onset of smoking when compared to the risk of becoming a smoker when alcohol consumption started after entering senior high school. An increased frequency of drinking was also associated with starting smoking (OR =14.00, 95% CI = 8.08-24.26; 2-3 times/week vs. never). Similarly, an increase in drinking frequency resulted in less likelihood of smoking cessation. For instance, the data showed that, the subjects were 1/3 less likely to quit smoking. Paternal smoking had a significant impact on whether or not a child would quit smoking (OR = 0.55, 95% CI = 0.38-0.81) as compared to a child that had paternal and maternal non-smokers. This study suggested that drinking habits started earlier than smoking habits among adolescents. Many students had already experienced drinking before admission to senior high school, while the experience of smoking mostly typically started after admission to high school. These data show the urgency of developing anti-smoking educational programs that could be developed and introduced prior to admission to high school.

Genetic susceptibility to atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disorder with an increasing prevalence in industrialized countries. AD belongs to the group of allergic disorders that includes food allergy, allergic rhinitis, and asthma. A multifactorial background for AD has been suggested, with genetic as well as environmental factors influencing disease development. Recent breakthroughs in genetic methodology have greatly augmented our understanding of the contribution of genetics to susceptibility to AD. A candidate gene association study is a general approach to identify susceptibility genes. Fifty three candidate gene studies (50 genes) have identified 19 genes associated with AD risk in at least one study. Significant associations between single nucleotide polymorphisms (SNPs) in chemokines (chymase 1-1903A > G), cytokines (interleukin13 Arg144Gln), cytokine receptors (interleukin 4 receptor 1727G > A) and SPINK 1258G > A have been replicated in more than one studies. These SNPs may be promising for identifying at-risk individuals. SNPs, even those not strongly associated with AD, should be considered potentially important because AD is a common disease. Even a small increase in risk can translate to a large number of AD cases. Consortia and international collaborative studies, which may maximize study efficacy and overcome the limitations of individual studies, are needed to help further illuminate the complex landscape of AD risk and genetic variations.

NQO1, MPO, and the risk of lung cancer: a HuGE review

The aim of this study is to summarize the available molecular epidemiologic studies of lung cancer and metabolic genes, such as NAD(P)H quinone reductase 1 (NQO1) and myeloperoxidase (MPO). NQO1 plays a dual role in the detoxification and activation of procarcinogens whereas MPO has Phase I activity by converting lipophilic carcinogens into hydrophilic forms. Variant genotypes of both NQO1 Pro187 Ser and MPO G-463A polymorphisms may be related to low enzyme activity. The Pro/Ser and Ser/Ser genotypes combined of NQO1 was significantly associated with decreased risk of lung cancer in Japanese [random effects odds ratio (OR) = 0.70, 95% confidence interval (CI) = 0.56-0.88] among whom the variant allele is common. The variant genotype of MPO was associated with decreased risk of lung cancer among Caucasians (random effects OR = 0.70, 95% CI = 0.47-1.04). Gene-environment interactions in both polymorphisms may be hampered by inaccurate categorization of tobacco exposure. Evidence on gene-gene interactions is extremely limited. As lung cancer is a multifactorial disease, an improved understanding of such interactions may help identify individuals at risk for developing lung cancer. Such a study should include larger sample size and other polymorphisms in the metabolism of tobacco-derived carcinogens and address interactions with smoking status. The effects of polymorphisms are best represented by their haplotypes. In future studies on lung cancer, the development of haplotype-based approaches will facilitate the evaluation of haplotypic effects, either for selected polymorphisms physically close to each other or for multiple genes within the same drug-metabolism pathway.

Association of polymorphisms in complement component C3 gene with susceptibility to systemic lupus erythematosus

OBJECTIVE

Identification of the genes responsible for systemic lupus erythematosus (SLE).

METHODS

All the exons and putative promoter regions of 53 candidate genes (TNFRSF6/Fas, TNFSF6/FasL, Fli1, TNFSF10/TRAIL, TNFSF12/TWEAK, Bcl-2, PTEN, FADD, TRADD, CDKN1A, TNFRSF1A/TNFR1, TNFRSF4/OX40, TNFSF4/OX40L, TNFSF5/CD40L, TNFSF13B/BAFF, ICOS, CTLA4, CD28, FYN, G2A, CR2, PTPRC/CD45, CD22, CD19, Lyn, PDCD1, PTPN6, TGFB1, TGFB2, TGFB3, TGFBR1, TGFBR2, TGFBR3, CD3Z, DNASE1, APCS, MERTK, C3, C1QA, C1QB, C1QG, C2, MBL2, IGHM, IL-2, IL-4, IL-10, IFNG, TNFA, MAN2A1, TNFRSF11A/RANK, TNFRSF11B/OPG, TNFSF11/OPGL) were screened for single nucleotide polymorphisms (SNPs) and their association with SLE was assessed by case-control studies. A total of 509 cases and 964 controls of Japanese descent were enrolled.

RESULTS

A total of 316 SNPs was identified. When analysed in the Japanese population, the allele frequencies of T at rs7951 and G at rs2230201 of the C3 gene were 0.110 and 0.626, respectively, in SLE patients; significantly higher than the frequencies of 0.081 and 0.584, respectively, in controls [odds ratio (OR) = 1.40, 95% confidence interval (CI) = 1.05-1.86, P = 0.016 and OR=1.19, 95% CI = 1.01-1.41, P = 0.038, respectively]. The mean serum C3 level of carriers of the rs7951 T allele was significantly lower than that of non-carriers of the T allele in 87 SLE patients whose medical records were available (P = 0.0018).

CONCLUSION

rs7951 T allele of the C3 gene was significantly associated with SLE, and decreased serum level of C3 seems to be correlated with this allele.

Lung cancer susceptibility: are we on our way to identifying a high-risk group?

Many studies have investigated lung cancer susceptibility based on the presence of low-penetrance, high-frequency single nucleotide polymorphisms. Identifying such susceptibility polymorphisms may lead to the development of tests that allow a more focused follow-up of a high-risk group. Genetic polymorphisms of xenobiotic metabolism, DNA repair, cell-cycle control, immunity, addiction and nutritional status have been described as promising candidates. Genetic polymorphisms in both metabolic activation (Phase I) and detoxification (Phase II) enzymes influence DNA damage. The DNA repair system is a critical cellular response that counteracts the carcinogenic effects of DNA. Thus, genetically determined susceptibility to carcinogens depends on the balance between metabolic and DNA repair enzymes. This review evaluates whether or not a specific polymorphism or a combination of such polymorphisms can effectively predict high-risk groups.

Environmental factors and allergic disorders

Despite numerous studies on possible associations between environmental exposure and allergic disorders, any conclusions made remain a matter of controversy. We conducted a review of evidence in relation to environmental and nutritional determinants and wheeze, asthma, atopic dermatitis, and allergic rhinitis. Identified were 263 articles for analysis after consideration of 1093 papers that were published since 2000 and selected by electronic search of the PubMed database using keywords relevant to epidemiological studies. Most were cross-sectional and case-control studies. Several prospective cohort studies revealed inconsistent associations between various environmental factors and the risk of any allergic disorder. Therefore, the evidence was inadequate to infer the presence or absence of a causal relationship between various environmental exposures and allergic diseases. However, evidence is suggestive of positive associations of allergies with heredity. Because almost all the studies were performed in Western countries, the application of these findings to people in other countries, including Japan, may not be appropriate. Further epidemiological information gained from population-based prospective cohort studies, in particular among Japanese together with other Asians, is needed to assess causal relationships between various environmental factors and allergic diseases.

Differences in developing intestinal microbiota between allergic and non-allergic infants: a pilot study in Japan

The bacterial compositions of feces were monitored in the first 2 months for 15 infants born in Japan, including eight subjects who developed allergy by the age of 2 years. Primer sets targeting six predominant bacterial groups in the infant intestine, Bacteroidaceae, Enterobacteriaceae, bifidobacteria, enterococci, lactobacilli, and the Clostridium perfringens group, were used for real-time PCR to quantitate each population in the feces. The population of Bacteroidaceae was significantly higher in the allergic group at the ages of 1 month (P=0.03) and 2 months (P=0.05) than in the non-allergic group, while no statistically significant difference was observed for the other bacterial populations.

Home environment and suspected atopic eczema in Japanese infants: the Osaka Maternal and Child Health Study

Atopic eczema is most commonly diagnosed in children under the age of 5 yr. Environmental factors during pregnancy or in early life may confer risk for childhood atopic eczema. The present prospective study examined the relationship of the perinatal home environment and the risk of suspected atopic eczema among Japanese infants under the age of 1. Study subjects were 865 parent-child pairs. The term 'suspected atopic eczema' was used to define an outcome based on our questionnaire at 2-9 months postpartum. Adjustment was made for maternal age, gestation, family income, maternal and paternal education, maternal and paternal history of asthma, atopic eczema, and allergic rhinitis, time of delivery before the second survey, baby's older siblings, baby's sex, and baby's birth weight. A high mite allergen level from maternal bedclothes and mold in the kitchen during pregnancy were significantly associated with an increased risk of suspected atopic eczema. Frequent vacuuming practices during pregnancy and giving the infant a bath or shower at least once a day were significantly inversely related to the risk of suspected atopic eczema. Maternal smoking, maternal use of a synthetic duvet and pillow, carpet use in the living room and maternal bedroom, indoor domestic pets, no ducted heating appliance, and gas use for cooking during pregnancy and household smoking in the same room as the infant, infant's synthetic duvet, carpet use in the infant's room, or vacuuming the infant's room were not related to the risk of suspected atopic eczema. High house dust mite allergen levels and mold in the kitchen during pregnancy may increase the risk of infantile atopic eczema, whereas frequent vacuuming practices during pregnancy and giving the infant a bath or shower at least once a day may protect against infantile atopic eczema.

Polymorphisms of cytochrome P450 1A1, glutathione S-transferase class mu, and tumour protein p53 genes and the risk of developing gallbladder cancer in Japanese

OBJECTIVES

To examine the relationship between genetic polymorphisms of cytochrome P450 1A1 (CYP1A1), glutathione S-transferase class mu (GSTM1), and tumour protein p53 (TP53) genes, and gallbladder cancer (GBC) risk, a case-control study was conducted.

DESIGN AND METHODS

Genotypes of CYP1A1 T3801C, CYP1A1 Ile462Val, GSTM1, and TP53 Arg72Pro were determined in 54 cases of GBC and 178 controls.

RESULTS

The age-adjusted odds ratios (ORs) for the Ile/Val genotype of CYP1A1 Ile462Val polymorphism in women and the Arg/Pro genotype of TP53 Arg72Pro polymorphism in men were observed to be 2.70 (95% CI: 1.14-6.40) and 4.32 (95% CI: 1.08-17.2), respectively. No significant differences in the genotypic frequencies of CYP1A1 T3801C and GSTM1 polymorphisms were observed between controls and cases in both men and women.

CONCLUSION

These results suggest that the Val allele of CYP1A1 Ile462Val polymorphism and the Pro allele of TP53 Arg72Pro polymorphism contribute to an increased risk of GBC among Japanese women and men, respectively.

Evidence of gene gene interactions in lung carcinogenesis in a large pooled analysis

To test the hypothesis of interaction among genetic variants in increasing the individual risk of cancer, we have studied the cumulative effect on lung cancer risk of variants in three metabolic genes, CYP1A1, GSTM1 and GSTT1, which are involved in the metabolism of the tobacco smoke constituents and environmental contaminants, polycyclic aromatic hydrocarbons and of other lung carcinogens. We have selected from the Genetic Susceptibility to Environmental Carcinogens pooled analysis all the studies on lung cancer conducted after 1991 in which all variants were available. The data set includes 611 cases and 870 controls. We found a cumulative effect of the combination of the a priori 'at-risk' alleles for these genes (P for trend 0.004). The risk of lung cancer was increased with the combination of CYP1A1*2B or CYP1A1*4 alleles and the double deletion of both GSTM1 and GSTT1 up to an odds ratio (OR) of 8.25 (95% confidence interval 2.29-29.77) for the combination including CYP1A1*4; among never smokers, the latter combination was associated with an OR of 16.19 (1.90-137). Estimates did not change after adjustment by the number of cigarettes smoked and duration of smoking were consistent across ethnicities and were approximately the same for adenocarcinomas and squamous cell carcinomas. These observations from a large pooled analysis strongly suggest the existence of gene-gene interactions in lung carcinogenesis. People with rare combinations of common gene variants have a high risk of cancer and can be assimilated to subjects with highly penetrant mutations.

Genetic polymorphisms in the nucleotide excision repair pathway and lung cancer risk: a meta-analysis

Various DNA alterations can be caused by exposure to environmental and endogenous carcinogens. Most of these alterations, if not repaired, can result in genetic instability, mutagenesis and cell death. DNA repair mechanisms are important for maintaining DNA integrity and preventing carcinogenesis. Recent lung cancer studies have focused on identifying the effects of single nucleotide polymorphisms (SNPs) in candidate genes, among which DNA repair genes are increasingly being studied. Genetic variations in DNA repair genes are thought to modulate DNA repair capacity and are suggested to be related to lung cancer risk. We identified a sufficient number of epidemiologic studies on lung cancer to conduct a meta-analysis for genetic polymorphisms in nucleotide excision repair pathway genes, focusing on xeroderma pigmentosum group A (XPA), excision repair cross complementing group 1 (ERCC1), ERCC2/XPD, ERCC4/XPF and ERCC5/XPG. We found an increased risk of lung cancer among subjects carrying the ERCC2 751Gln/Gln genotype (odds ratio (OR) = 1.30, 95% confidence interval (CI) = 1.14 - 1.49). We found a protective effect of the XPA 23G/G genotype (OR = 0.75, 95% CI = 0.59 - 0.95). Considering the data available, it can be conjectured that if there is any risk association between a single SNP and lung cancer, the risk fluctuation will probably be minimal. Advances in the identification of new polymorphisms and in high-throughput genotyping techniques will facilitate the analysis of multiple genes in multiple DNA repair pathways. Therefore, it is likely that the defining feature of future epidemiologic studies will be the simultaneous analysis of large samples.

Risk of postpartum depression in relation to dietary fish and fat intake in Japan: the Osaka Maternal and Child Health Study

BACKGROUND

An ecological analysis found that the docosahexaenoic acid content in mother's milk and seafood intake were inversely correlated with postpartum depression. This prospective study investigated the relationship of consumption of selected high-fat foods and specific types of fatty acids with the risk of postpartum depression.

METHOD

The subjects were 865 Japanese women. Dietary data were obtained from a self-administered diet history questionnaire during pregnancy. The Edinburgh Postnatal Depression Scale (EPDS) was used for the evaluation of postpartum depression. Adjustment was made for age, gestation, parity, cigarette smoking, family structure, family income, education, changes in diet in the previous month, season when data at baseline were collected, body mass index, time of delivery before the second survey, medical problems in pregnancy, baby's sex and baby's birthweight.

RESULTS

The percentage of women with high depression scores was 14.0%. No evident dose-response associations were observed between intake of fish, meat, eggs, dairy products, total fat, saturated fatty acids, monounsaturated fatty acids, n-3 polyunsaturated fatty acids, n-6 polyunsaturated fatty acids, linoleic acid, alpha-linolenic acid, arachidonic acid, eicosapentaenoic acid or docosahexaenoic acid and the ratio of n-3 to n-6 polyunsaturated fatty acids and the risk of postpartum depression. However, there was an inverted J-shaped relationship between intake of n-3 polyunsaturated fatty acids and docosahexaenoic acid and the risk of postpartum depression.

CONCLUSIONS

This study failed to substantiate a clear inverse relationship between fish and n-3 polyunsaturated fatty acid intake and postpartum depression. Further investigations are needed to determine whether fish and n-3 polyunsaturated fatty acid consumption is preventive against postpartum depression.

Meta- and pooled analysis of GSTT1 and lung cancer: a HuGE-GSEC review

Lung cancer is the most common malignancy in the Western world, and the main risk factor is tobacco smoking. Polymorphisms in metabolic genes may modulate the risk associated with environmental factors. The glutathione S-transferase theta 1 gene (GSTT1) is a particularly attractive candidate for lung cancer susceptibility because of its involvement in the metabolism of polycyclic aromatic hydrocarbons found in tobacco smoke and of other chemicals, pesticides, and industrial solvents. The frequency of the GSTT1 null genotype is lower among Caucasians (10-20%) than among Asians (50-60%). The authors present a meta- and a pooled analysis of case-control, genotype-based studies that examined the association between GSTT1 and lung cancer (34 studies, 7,629 cases and 10,087 controls for the meta-analysis; 34 studies, 7,044 cases and 10,000 controls for the pooled analysis). No association was observed between GSTT1 deletion and lung cancer for Caucasians (odds ratio (OR) = 0.99, 95% confidence interval (CI): 0.87, 1.12); for Asians, a positive association was found (OR = 1.28, 95% CI: 1.10, 1.49). In the pooled analysis, the odds ratios were not significant for either Asians (OR = 0.97, 95% CI: 0.83, 1.13) or Caucasians (OR = 1.09, 95% CI: 0.99, 1.21). No significant interaction was observed between GSTT1 and smoking on lung cancer, whereas GSTT1 appeared to modulate occupational-related lung cancer.

Dietary folate and vitamins B12, B6, and B2 intake and the risk of postpartum depression in Japan: the Osaka Maternal and Child Health Study

BACKGROUND

Previous studies showed an inverse association between folate intake and depression. However, epidemiological evidence for folate intake and postpartum depression is unavailable. This prospective study examined the relationship of dietary consumption of folate and B vitamins during pregnancy with the risk of postpartum depression.

METHODS

Study subjects were 865 Japanese women. Dietary data were obtained during pregnancy from a validated self-administered diet history questionnaire. Postpartum depression was defined as present when subjects had an Edinburgh Postnatal Depression Scale score of 9 or higher between 2 and 9 months postpartum. Adjustment was made for age, gestation, parity, cigarette smoking, alcohol intake, family structure, family income, education, changes in diet in the previous 1 month, season when data at baseline were collected, body mass index, time of delivery before the second survey, medical problems in pregnancy, baby's sex, and baby's birth weight.

RESULTS

Postpartum depression developed in 121 subjects (14.0%) 2 to 9 months postpartum. There was no measurable association between intake of folate, cobalamin, or pyridoxine and the risk of postpartum depression. Compared with riboflavin intake in the first quartile, only riboflavin consumption in the third quartile was independently related to a decreased risk of postpartum depression (multivariate odds ratio: 0.53, 95% CI: 0.29-0.95, P for trend=0.55).

LIMITATIONS

Personal and family psychiatric history, sociocultural factors, and personal and family relations were not controlled for. The possibility of misclassification of dietary information during pregnancy should be considered.

CONCLUSIONS

Our results suggest that moderate consumption of riboflavin may be protective against postpartum depression.

Smoking, drinking, sleeping habits, and other lifestyle factors and the risk of systemic lupus erythematosus in Japanese females: findings from the KYSS study

Many risk factors have been proposed for systemic lupus erythematosus (SLE). However, there is little information about the relationship between lifestyles and SLE in Japan. Two case control studies were conducted in Kyushu, southern Japan, and in Hokkaido, northern Japan, to examine the relationship between lifestyles and development of SLE in females. The participants were 78 patients and 329 controls in Kyushu and 35 patients and 188 controls in Hokkaido. Smoking was associated with an increased risk of SLE after adjusting for age in both regions. However, in Hokkaido, this association between smoking and SLE did not reach statistical significance after adjusting for alcohol drinking. The present study suggests that smoking may increase the risk of SLE among Japanese females.

A functional M196R polymorphism of tumour necrosis factor receptor type 2 is associated with systemic lupus erythematosus: a case-control study and a meta-analysis

OBJECTIVES

To perform a case-control study of a functional M196R polymorphism of tumour necrosis factor receptor type 2 (TNF-RII) in a Japanese population and a meta-analysis of all published reports on the polymorphism to investigate the association of the M196R polymorphism of TNF-RII with systemic lupus erythematosus (SLE).

METHODS

The functional M196R polymorphism of TNF-RII was genotyped by using polymerase chain reaction combined with the subsequent single-strand conformation polymorphism (PCR-SSCP) analysis for screening, followed by nucleotide sequencing for confirmation. A total of 331 patients and 359 controls were subjected to a case-control study. A meta-analysis of the available case-control studies including all published data as well as our own data was performed to investigate the association of the functional M196R polymorphism of TNF-RII with SLE.

RESULTS

Our case-control study did not show any significant association of a functional M196R polymorphism of TNF-RII with SLE, although there was a trend towards association. A meta-analysis of seven case-control studies in eight different ethnic populations including our own showed that 196M/R and 196R/R genotypes combined was significantly associated with an increased risk of SLE (odds ratio (OR) 1.29, 95% confidence interval (CI) 1.04 to 1.60; p = 0.02). Stratification by ethnicity showed a more significant association in Asians, including Japanese, Korean and Vietnamese (OR 1.40, 95% CI 1.10 to 1.78; p = 0.006). The effect of the 196R allele on SLE was not clear in Caucasians.

CONCLUSIONS

The 196R allele of the functional M196R polymorphism of TNF-RII is a risk factor for SLE, especially in the Asian population.

[Epidemiology, treatment and prevention of attention deficit/hyperactivity disorder: a review]

Attention deficit/hyperactivity disorder (ADHD) is characterized by inattentiveness and/or impulsiveness and hyperactivity, which are unsuited for the developmental stage or age. Although mechanisms leading to the onset of the disease are unclear, this condition seriously hinders childrens' social or learning functions, and recently it was selected as a target disease for a special supporting education program by the Minitry of Education, Culture, Sports, Science and Technology, together with learning disorders and high-functioning pervasive developmental disorders in Japan. In spite of the increasing social interest in ADHD, the epidemiological evidence including data for incidence, prevalence, gender differences, and etiology remain insufficient. In Western countries, as represented by the United States, operational diagnostic criteria such as DSM-IV are widely used and several diagnostic processes using structured interviews have been established. However, the diagnostic criteria have not been consistent even within DSM as shown by DSM-IV and DSM-III-R, and therefore basic epidemiological evidence was not consistent in the previous studies. Regarding the etiology of ADHD, exposure to addictive substances during the pregnancy period caused by maternal smoking or drinking, and familial socioeconomic status are considered important environmental factors. In addition, a family history of mental disorders and polymorphisms of dopamine-related genes such as DRD4 or SLC6A3 have been noted as genetic factors concerning the development of ADHD. However, in Japan, no studies of these subjects or gene-environment interactions have so far been performed. Thus, epidemiological assessment of other than Western populations is needed. In the clinical situation, it is important to grasp the timing of treatment and target problems on the basis of changes of children's ability to control their attention or behavior, and environmental factors associated with growth processes. Especially, comorbidity such as conduct disorder or oppositional defiant disorder is a critical problem. Thus, considering that ADHD is a multifactorial disease, a comprehensive therapic strategy involving medication, education, judicature, and administration should be established for primary and secondary prevention.