[Distribution of HLA-G 14 bp insertion/deletion polymorphism and their associations with HLA-A alleles in four Chinese ethnic groups].

Recently, a 14 bp insertion/deletion polymorphism (+14 bp/-14 bp) in exon 8 of the human leucocyte antigen-G (HLA-G) gene has been widely recognized to associate with recurrent miscarriage, autoimmune diseases, hepatocellular carcinoma and other diseases. Our previous studies have shown the distribution characteristics of linguistic family for HLA-G 14 bp insertion/deletion in different ethnic groups. In the present study, we investigated the distribution of HLA-G 14 bp insertion/deletion polymorphism and their subsequent associations with HLA-A alleles in Tu, Yugu, Lisu and Nu ethnic populations based upon the HLA-A genotyping data. Our results showed that the frequencies of the 14 bp insertion/deletion polymorphism were diverse in these four populations while that in the same linguistic subfamily was similar. The significant difference in different linguistic subfamily except for Han and Mongolian language subfamily was identified. In addition, the 14 bp insertion was found to associate with HLA-A alleles in different ethnic populations.

[Association between Alu insertion polymorphisms and HLA class I alleles in Chinese Lisu and Nu ethnic populations].

OBJECTIVE: To investigate the frequencies of HLA-Alu repeat polymorphisms (AluMICB, AluTF, AluHJ, AluHG and AluHF) in Chinese Lisu and Nu ethnic populations. METHODS: The frequencies of HLA-Alu repeat polymorphisms in above populations were determined with polymerase chain reaction (PCR). The associations between HLA-Alu repeat polymorphisms and HLA-A, HLA-B and HLA-C alleles were also analyzed. Phylogenetic trees were constructed with genetic distance calculated from the frequencies of HLA-Alu repeat polymorphisms. RESULTS: Frequencies of AluTF*2 and AluHF*2 were different between the two populations (P< 0.05), while those of other three insertions were similar. The strength of association between HLA-Alus and HLA alleles were different (P< 0.05) in the two populations. Although AluMICB*2 were associated with HLA-B*56:01 in both populations, the association was stronger in Lisu population (74.0%) but moderate in Nu population (30.7%). HLA-Alus were associated with particular HLA subtypes, e.g., AluHG*2 with certain HLA-A*02 subtypes. By phylogenetic analysis, Lisu and Nu were clustered together with southern Chinese and Thai populations. CONCLUSION: The distribution of HLA-Alus and the strength of associations between HLA-Alus and HLA class I alleles have varied between the two populations. Study of this association may facilitate identification of origins, evolution, progenitor haplotypes and recombination within the HLA class I region.

[Detection and preliminary study of a family carrying a CCR5Δ32 deletional mutation].

OBJECTIVE: To investigate the frequencies of chemokine (C-C motif) receptor 5 gene (CCR5)Δ32 deletional mutation of in Han and Dai populations from Yunnan province. Immortalized cell lines were derived from a family carrying the CCR5Δ32 mutation. METHODS: Blood samples of 346 Han and 355 Dai individuals were collected for genotyping. The coding regions of CCR5 gene were amplified with PCR followed by agarose gel electrophoresis. Suspected mutations were verified with DNA sequencing. Immortalized cell lines were constructed by using Epstain Barr virus and cyclosporine A. The difference between the cell lines and original blood samples was verified with PCR. RESULTS: One ethnic Han individual was confirmed to be heterozygous for a deletional mutation by sequencing, which has led to discovery of a family with CCR5Δ32. Nine immortalized cell lines were established from this family, and no difference between the cell lines and original blood samples was detected by PCR. CONCLUSION: Together with previous reports, this study has indicated a significant difference in CCR5Δ32 among different ethnic groups in China. Established immortalized cell lines can also provide material for future research.

[Distribution of HLA-C genes and HLA C-B, A-C-B haplotypes in Jinuo, Maonan and Wa ethnic populations in southwest China].

OBJECTIVE: To investigate the distribution of human leukocyte antigen(HLA) class I genes and haplotypes in Jinuo, Maonan and Wa ethnic populations in southwest China. METHODS: Polymerase chain reaction-sequence specific oligonucleotide (PCR-SSO) typing by Luminex was performed to genotype the HLA-C alleles in unrelated healthy individuals in the three populations. HLA C-B, A-C-B haplotypes were computed by combining the previous HLA-A and -B genotyping data using Pypop7.0 software. RESULTS: Eighteen HLA-C genes were identified in the three populations, with 17, 13 and 15 HLA-C genes in Jinuo, Maonan and Wa populations respectively. The alleles with frequency of more than 10% from high to low were C*08:01, C*01:02, C*03:04 and C*07:02 in the Jinuo, C*03:04, C*01:02, C*07:02 and C*08:01 in the Maonan, and C*12:03, C*08:01, C*07:02 and C*04:01 in the Wa. The predominant HLA A-C-B haplotypes were A*02:07-C*01:02-B*46:01, A*11:01-C*08:01-B*15:02 and A*11:01-C*03:04-B*13:01 in the Jinuo, A*11:01-C*03:04-B*13:01, A*02:07-C*01:02-B*46:01, A*11:01-C*08:01-B*15:02 and A*02:03-C*07:02-B*38:02 in the Maonan, and A*11:01-C*08:01-B*15:02, A*11:01-C*12:03-B*15:32 and A*11:01-C*04:01-B*35:01 in the Wa, respectively. CONCLUSION: There were different characteristics in the distributions of HLA-C genes and HLA C-B, A-C-B haplotypes in the Jinuo, Maonan and Wa populations. However, haplotypes C*08:01-B*15:02 and A*11:01-C*08:01-B*15:02 with high frequencies were common in the three populations, which might be the common ancient haplotypes of southern Chinese population. The study of HLA genes and haplotypes in these populations may be of significance in the study of population genetics, transplantation and disease association.

[Association between diversity of hypoxia at different altitude and the polymorphism of EPAS1 gene].

OBJECTIVE: To study the selection effect of endothelial PAS domain protein 1 (EPAS1) gene induced by high altitude hypoxia environment. METHODS: Fourteen single nucleotide polymorphism sites (SNPs) of the EPAS1 gene were genotyped using PCR-restriction fragment length polymorphism (PCR-RFLP) in three Tibetan groups (58 samples from Tibetan living in an altitude of about 3700 meters above sea level, 47 from Qinghai province, about 3100 meters above sea level, 43 from Yunnan province, about 2500 meters above sea level), and Han of Shandong (47 samples, about 50 meters above sea level). RESULTS: There were significant differences of most SNP allelic, genotypic and haplotypic frequencies when comparing Han of Shandong, Tibetan of Yunnan with Tibetan of Tibetan and Qinghai. But no difference between Han of Shandong and Tibetan of Yunnan was found. CONCLUSION: The EPAS1 gene might be under hypoxic selection induced by high altitude.

[Polymorphic Alu insertions and their associations with HLA I alleles in Yugu and Zhuang ethnic populations].

Many studies have show that the structurally polymorphic Alu insertion within HLA class I region are useful tools for investigating the origin, evolution and recombination of HLA class I progenitor haplotypes and gene diversity in different ethnic populations. In the present study, we determined the frequencies of HLA-Alus (i.e., AluMICB, AluTF, AluHJ, AluHG, and AluHF) in Zhuang and Yugu ethnic populations at first. Then, combined with HLA genotyping data, we studied associations between HLA-Alus and HLA-A alleles in Zhuang, Yugu, Bulang, Dai, and Hani ethnic populations. Our results showed that (1) the frequencies of five HLA-Alus were 1.5%~35.8% and 9.2%~34.8% in Zhuang and Yugu, respectively; and (2) the results of association between HLA-A alleles and HLA-Alu showed strong association between AluHG insertion and HLA-A 02 subtypes in all populations, association between AluHJ insertion and HLA-A 2402 in all populations, and association between AluHJ insertion and HLA-A 1101, -A 2407 in Bulang. The present study suggested that the distribution of HLA-Alus as well as the associations between HLA-Alus and HLA class I alleles are variable in different ethnic populations. HLA Alus alone or together with the HLA class I alleles are informative genetic markers for the identification of HLA class I allele and variation of haplotype lineages in different populations.

[Study of nine single nucleotide polymorphism loci of human HIF1A gene in three Tibetan groups].

OBJECTIVE: To investigate the effect of hypoxia environment induced by altitude on hypoxia inducible factor 1α (HIF1A) gene. METHODS: Nine single nucleotide polymorphism (SNP) loci of the HIF1A gene from three Tibetan groups (Tibet, Qinghai Province and Yunnan Province) were genotyped using PCR-restriction fragment length polymorphism (PCR-RFLP) method. RESULTS: For non-synonymous mutation SNP site, there was no significant difference among the three Tibetan groups, except for SNP rs11549465 between Tibet Tibetan and Yunnan Tibetan, as well as between Qinghai Tibetan and Yunnan Tibetan. Frequencies of genotypes and alleles in rs4899056, rs1957757, rs10873142 and rs3783752 had significant differences between Tibet Tibetan and Yunnan Tibetan, and between Qinghai Tibetan and Yunnan Tibetan (all P<0.05). We also observed that the difference was negatively correlated with the altitude. CONCLUSION: The results suggested that the HIF1A gene might be under hypoxic selection induced by high altitude in the three groups.

[Analysis of the 14 bp insertion/deletion polymorphism in human leukocyte antigen-G gene in Chinese Dai and Han ethnic groups in Yunnan Province].

A 14 bp insertion/deletion polymorphism (+14 bp/-14 bp) in exon 8 of HLA-G gene has been investigated extensively because this polymorphism was associated with HLA-G mRNA stability and could influence HLA-G mRNA expression. In the present study, we genotyped 14 bp insertion/deletion polymorphisms in the HLA-G gene in Dai and Han populations in Yunnan Province. The frequencies of +14 bp in Dai and Han were 31.97% and 40.87%, respectively. The frequency of +14 bp/+14 bp in Dai was lower (8.20%) than that of Han (17.31%). Nevertheless, the frequency of +14 bp/-14 bp was similar in both populations (47.54% in Dai and 47.11% in Han). When compared with other populations, the frequency of 14 bp insertion/deletion of Han was similar to others, whereas the Dai showed significant difference from others and presented it's specific characteristic. We assumed that the distribution characteristic of 14 bp insertion/deletion in Dai might be the results of random genetic drift, but the role of natural selection cannot be excluded.

Alcohol-related disorders in Beijing, China: prevalence, socio-demographic correlates, and unmet need for treatment.

BACKGROUND: The study aimed to determine the prevalence of alcohol use, episodic heavy drinking, and alcohol dependence and their socio-demographic correlates in Beijing, China. methods: A total of 5,926 subjects were randomly selected in Beijing and interviewed using the Composite International Diagnostic Interview (CIDI 1.0). Data on basic socio-demographic and current major medical conditions were also collected. RESULTS: The 12-month prevalence of alcohol use and episodic heavy drinking were 32.5 and 13.8%, respectively. The 12-month and lifetime prevalence of alcohol dependence were 1.7 and 4.3%, respectively. Age above 24 years, male sex, being married and employed, low education level (junior high school, primary school or illiterate), rural residence, and having comorbid psychiatric disorders were all significantly associated with a higher likelihood of alcohol-related disorders. Only 2.4% of the subjects with alcohol dependence were receiving treatment, and a mere 1.4% had sought treatment from mental health professionals. CONCLUSIONS: Nationwide surveys are urgently needed to further explore the prevalence of alcohol-related disorders in China.

Lifetime prevalence of suicidal ideation, suicide plans and attempts in rural and urban regions of Beijing, China.

OBJECTIVE: There has been no large-scale survey of suicide-related behaviours including suicidal ideations, plans and attempts in China involving both rural and urban areas and using standardized assessment tools. The aim of the present study was to determine the lifetime prevalence of suicide-related behaviour and its relationship with sociodemographic factors and psychiatric disorders in the rural and urban regions of Beijing, China. METHODS: A total of 5926 subjects were randomly selected in Beijing and interviewed using the Composite International Diagnostic Interview. Basic sociodemographic and clinical data and data on suicide-related behaviour were also collected. RESULTS: The overall lifetime prevalence estimates of suicidal ideation, plans and attempts were 2.3%, 1.4%, and 1.0%, respectively; the corresponding figures were 2.8%, 1.6%, and 1.3% in the rural sample, and 1.8%, 1.3%, and 0.9% in the urban sample. Age (>25 years), female sex, unmarried status, lower education level, lower (RMB2000 month(-1)) monthly income and presence of major medical disorders were significantly associated with increased risk of suicide-related behaviour. 36.2% of subjects with suicide-related behavior consulted a medical practitioner and 20.7% consulted a psychiatrist. CONCLUSIONS: The prevalence of lifetime suicide-related behaviour in Beijing is lower than in Western countries, but the low percentage of subjects treated for suicide-related behaviour indicates a major public health problem that should be addressed. National surveys are needed to further explore the prevalence of suicide-related behaviour in China.

[Establishment of immortalized cell lines and genetic stability evaluation for a family with spinocerebellar ataxia type 2].

OBJECTIVE: Immortalized cell lines of spinocerebellar ataxia type 2 (SCA2) with Parkinson disease symptoms were established in order to provide experimental material for future study. METHODS: The immortalized cell lines were constructed by using Epstein Barr virus and cyclosporine A. Microsatellite markers were detected to see whether there is any change between the cell lines and the original blood samples, and the genetic stability of the cell lines were evaluated. RESULTS: Twenty-five immortalized cell lines were established successfully from the family and the microsatellite markers were unchanged. CONCLUSION: The karyotypes of the immortal cell lines were normal and the cell lines were genetically stable.

The prevalence of insomnia, its sociodemographic and clinical correlates, and treatment in rural and urban regions of Beijing, China: a general population-based survey.

STUDY OBJECTIVES: To determine the prevalence of insomnia, its sociodemographic and clinical correlates, and treatment patterns in Chinese people. DESIGN: A total of 5,926 subjects were randomly selected in the urban and rural areas of Beijing and interviewed using standardized assessment tools. Basic sociodemographic and clinical data were also collected. SETTING: Urban and rural regions of Beijing municipality, China. Patients or Participants Adult residents older than 15 years. Interventions N/A. MEASUREMENTS AND RESULTS: The prevalence of at least one type of insomnia was 9.2%; the rates of difficulty initiating sleep (DIS), difficulty maintaining sleep (DMS), and early morning awakening (EMA) were 7.0%, 8.0%, and 4.9%, respectively. Increased age (age >44 and 24 years in the urban and rural samples, respectively), female sex, married, divorced, separated, or widowed marital status; having a major medical condition; and suffering from a psychiatric disorder were risk factors for all types of insomnia in both the urban and rural samples. A low level of education (primary school or illiteracy) was significantly associated with a higher likelihood of all types of insomnia in the urban sample. Current smokers and current drinkers were less likely to report any type of insomnia in the rural sample. Unemployment was associated with DMS in the urban sample, while it was associated with DIS and DMS in the rural sample. Only 5.4% of the participants with any type of insomnia reported their symptoms to medical practitioners. In contrast, nearly one-third of the subjects with insomnia reported taking benzodiazepines as sleep-enhancing drugs. CONCLUSIONS: Nationwide epidemiologic surveys are needed to further explore the prevalence of insomnia in China. The low percentage of subjects treated for insomnia indicates a major public health problem that should be addressed. Strict controls on use of benzodiazepines are warranted.

Prevalence and socio-demographic correlates of schizophrenia in Beijing, China.

OBJECTIVE: There has been no large-scale survey of schizophrenia in China involving both rural and urban areas using standardized assessment tools and diagnostic criteria. This study aimed to determine the lifetime prevalence of schizophrenia and its socio-demographic correlates in Beijing, China. METHODS: A total of 5926 subjects were randomly selected in Beijing and interviewed using the Composite International Diagnostic Interview (CIDI 1.0). Basic socio-demographic and clinical data were collected during the interviews. RESULTS: The lifetime prevalence of schizophrenia was 0.49%, and 0.44% and 0.55% for men and women, respectively. Unmarried status, lower monthly income, urban abode and positive family history were associated with an increased risk of schizophrenia; 9.7% of the subjects with lifetime schizophrenia reported a history of suicide attempts. The percentage of subjects with schizophrenia who were receiving treatment and their preference to seek treatment from mental health professionals were 58% and 29%, respectively. CONCLUSIONS: National surveys are urgently needed to further explore the prevalence of schizophrenia in China. The low percentage of subjects treated for schizophrenia is a serious public health issue that should be addressed in the near future.

[Study on the genetic stability of immortalized cell line of lymphocyte cell transformed by EB virus after long subculture process].

OBJECTIVE: To study the genetic stability of an immortalized cell line transformed by Epstein-Barr virus (EBV) after long subculture process. METHODS: In the present study, the genetic stability including chromosome diploidy, karyotypes and microsatellite DNA were evaluated with chromosome banding techniques and microsatellite DNA detection. The telomerase activity of the immortalized cell line was detected by using the telomerase assay kit. RESULTS: From passage 1 to 30, there were no change of the diploidy, karyotypes of chromosome and microsatellite DNA, and the telomerase activity is negative. CONCLUSION: This study indicates that the immortalized cell line remains stable genetically within limited passages.

[Comparative analysis of the complete mitochondrial genome between Tibetan and Han population].

OBJECTIVE: To construct the haplogroup and perform an analysis of mitochondrial whole-genome sequence in Tibetan and Han Chinese. Variations of nucleotide of mitochondrial DNA (mtDNA) were identified and compared between the Tibetan and Han population. METHODS: The mtDNA whole sequences of 40 Tibetan and 50 Han individuals were sequenced by an Applied Biosystems 3730 DNA automatic sequencer. The sequences were assembled using software phredPhrap16.0, and all assembled sequences were manually verified according to the criterion of rCRS (revised Cambridge Reference Sequence). The haplogroups of mtDNA were constructed using phylogenetic analysis according to the criteria of MITOMAP by Network method. The data were elucidated by integrated methods. RESULTS: Authors' results showed that all the pooled 90 subjects belonged to the Macrohaplogroup M and N, and were classified into 13 haplogroups. No differences were observed among the haplogroups of the two populations except for M9 haplogroup. A total of 21 variants were detected by comparing the mtDNA whole sequences between Tibetan and Han population; of those, 5 variants have not been reported before. In addition, we constructed the haplotypes of 5 variants harboring the D-loop region, and founded prominent difference in both supertype 1 and supertype 2 between Tibetan and Han population. CONCLUSION: The phylogenetic analysis indicates that the Tibetan and Han ethnic groups shared close maternal relationship in origin. The biological implication of the significant variants is worth elucidating; whether they are the results of adaptive selection or neutral selection or pathological variations need to be further studied.

[Polymorphism of DYS287 on Y chromosome in 28 ethnic populations of China].

OBJECTIVE: To investigate the polymorphism of DYS287 among 28 ethnic populations in 9 provinces of China. METHOD: YAP element was detected by Touchdown PCR amplification and 2% agarose gel electrophoresis. RESULTS: YAP+ frequencies in these ethnic populations were as follows: Zang 36.7%, Tu 23.8%, Yi 18.4%, Pumi 11.3%, Tajik 7.4%, Bai 6.7%, Jino 5.1%, Shandong Han 4%, Mulao 2.7%, and Maonan 1.3%. The rest ethnic populations in our study, including Gansu Han, Yunnan Han, Zhuangzu, Daizu, Lizu, Nuzu, Lisu, Naxi, Lahu, Dulong, Hani, Shezu, Weiwuer, Sala, Kerkizi, Dongxiang, Vazu, and Korea didn't carry YAP + element. CONCLUSIONS: Zangzu, Tuzu, Yizu, Pumi, Jino, and Baizu, which belong to Sino-Tibetan language family, carry a high YAP + frequency. Sala, Tuzu, and Tajik, regarded as Central Asia by origin in history and linguistics, also have a high YAP + frequency. Mulao and Maonan, which origin from "Baiyue" ancient ethnic groups, also have a considerable YAP + frequency.

[A simple and rapid methods used for silver staining and gel preservation].

This paper introduced the simple and rapid methods of silver staining and gel preservation. It was taken only about 10 and 15 minutes to stain a gel. The background of gel was light, the bands were clear, the sensibility was high and the stabilization was well by the method of silver staining. The gel preservation adopted a method named two-layer transparent plastic paper "Sandwich" which could keep the gel with primitive colors for a long time. The methods were used on PAG checking and SSCP typing of HLA and the results were satisfactory. The set of methods are expected to be widely used in laboratories.

[Polymorphism of HLA-DRB1 in Han population in Yunnan and comparison with 9 Han populations].

129 samples of Han population in Yunnan province were detected by polymerase chain reaction and microtitre plate hybridization (PCR-MPH). The samples of DR*15 subgroup being detected by PCR-MPH were further analyzed by Single-Strand Conformation Polymorphism (SSCP). By first polymerase chain reaction and microtitre plate hybridization (PCR-MPH), all of the 129 samples were divided into the following subgroups, viz. DR*01,DR*03,DR*04,DR*0701,DR*08,DR*09012,DR*1001,DR*11,DR*12,DR*13,DR*14,DR*15, DR*1602 and DR*1604. The samples of DR*04, DR*08/12, DR*03/11/13/14 were further detected by second PCR-MPH and the ones of DR*15 by SSCP. 36 kinds of alleles on HLA-DRB1 were detected in these samples. Among them, DRB1*1501(0.1240),DRB1*09012(0.0969), DRB1*08032(0.0930),DRB1*1202(0.0891),DRB1*1201(0.0814), DRB1 *1401(0.0775),DRB1 *0701(0.0620),are the most frequent. The chi(2) test of HLA-DRB1 alleles was done between Yunnan Han and the other 9 Han populations. In detail, comparing with Yunnan Han on the chi(2) test, the chi(2) values of few alleles in the few Han populations was more than 10, they were Xian Han(DR8,chi(2)=13.9712), Shanghai Han(DR4,chi(2)=10.1632), Guangdong Han(DR9,chi(2)=12.6121)and Nanjing Han(DR4,chi(2)=10.5796). Comparing with 9 Han populations, the genetic distance between Yunnan Han and Liaoning Han was the nearest(0.0541),Guangdong Han was the farthest(0.1851). In the 9 Han populations, the genetic distance between Shanghai Han and Nanjing Han was the nearest(0.0122),and the one between Tianjin Han and Shanxi Han was also nearer(0.0219). Based on above analysis, the conclusion may be deduced that the resource of Yunnan Han may be close to Liaoning Han and it was not a typical southern Han population though Yunnan Han are resident in the South. Some gene flow may be exit between Yunnan Han and the local minorities and made Yunnan Han become a special population.

HLA polymorphism of the Zhuang population reflects the common HLA characteristics among Zhuang-Dong language-speaking populations.

A study of the human leukocyte antigen (HLA) genetic characteristics in the Zhuang, the largest ethnic population in China, would provide insight into Zhuang history and give a useful tool for disease associations, transplantation, and anthropology. In the present study, we report the comprehensive HLA-A, HLA-B, HLA-C, and HLA-DRB1 alleles and haplotypes in the Zhuang population of southern China for the first time. A total of 13 HLA-A, 24 HLA-B, 22 HLA-C, and 18 HLA-DRB1 were identified in 104 Zhuang individuals. The frequencies of HLA-A*11:01, A*02:07, A*24:02, A*02:03, and A*33:03 on A loci, B*15:02, B*58:01, B*46:01, and B*13:01 on B loci, C*03:04, C*08:01, C*01:02, C*03:02, and C*07:02 on C loci, and DRB1*15:01, DRB1*16:02, DRB1*14:01, DRB1*15:02, and DRB1*03:01 on the DRB1 loci were >10%. The A*33:03-C*03:02-B*58:01-DRB1*03:01 and A*02:07-C*01:02-B*46:01-DRB1*14:01 haplotypes were predominant in the Zhuang. The phylogenetic tree, as well as the analysis of haplotypes, suggested that the Zhuang are genetically similar to southern Chinese populations, especially the Zhuang-Dong language-speaking populations, such as the Bouyei, Dai, and Maonan. Even though the Zhuang and southern Chinese populations shared common alleles and haplotypes, the Zhuang has maintained its unique genetic characteristics.

Relationships of sleep duration with sleep disturbances, basic socio-demographic factors, and BMI in Chinese people.

OBJECTIVE: This study aimed at determining the mean total sleep time (TST) and the relationship between sleep duration and basic socio-demographic factors and BMI sleep problems in Chinese subjects. METHOD: A total of 5926 subjects were randomly selected and interviewed using standardized assessment tools. RESULTS: The reported mean TST was 7.76 h. Short sleepers were significantly older than medium and long sleepers. There were more urban residents who were short sleepers than medium and long sleepers. Short sleepers reported more sleep problems than medium and long sleepers. Short and long sleepers reported more psychiatric disorders than medium sleepers in both sexes, and short sleepers also had more major medical conditions in women. Short sleepers had a lower BMI than medium and long sleepers after controlling for the effects of age and psychiatric disorders in women. CONCLUSIONS: Nationwide epidemiologic surveys in China are needed to further explore the relationship between sleep duration and sleep problems.