Evaluation of VTE, MACE, and Serious Infections Among Patients with RA Treated with Baricitinib Compared to TNFi: A Multi-Database Study of Patients in Routine Care Using Disease Registries and Claims Databases.

INTRODUCTION: The aim of this work is to evaluate baricitinib safety with respect to venous thromboembolism (VTE), major adverse cardiovascular events (MACE), and serious infection relative to tumor necrosis factor inhibitors (TNFi) in patients with rheumatoid arthritis (RA). METHODS: Patients with RA from 14 real-world data sources (three disease registries, eight commercial and three government health insurance claims databases) in the United States (n = 9), Europe (n = 3), and Japan (n = 2) were analyzed using a new user active comparator design. Propensity score matching (1:1) controlled for potential confounding. Meta-analysis of incidence rate ratios (IRR) and incidence rate differences (IRD) for each outcome, from each data source was executed using modified Poisson regression and Cochran-Mantel-Haenszel analysis. RESULTS: Of 9013 eligible baricitinib-treated patients, 7606 were propensity score-matched with TNFi-treated patients, contributing 5879 and 6512 person-years of baricitinib and TNFi exposure, respectively. Across data sources, 97 patients (56 baricitinib) experienced VTE during follow-up, 93 experienced MACE (54 baricitinib), and 321 experienced serious infection (176 baricitinib). Overall IRRs comparing baricitinib with TNFi treatment were 1.51 (95% CI 1.10, 2.08) for VTE, 1.54 (95% CI 0.93, 2.54) for MACE, and 1.36 (95% CI 0.86, 2.13) for serious infection. IRDs for VTE, MACE, and serious infection, respectively, were 0.26 (95% CI -0.04, 0.57), 0.22 (95% CI -0.07, 0.52), and 0.57 (95% CI -0.07, 1.21) per 100 person-years greater for baricitinib than TNFi. CONCLUSIONS: Overall results suggest increased risk of VTE with baricitinib versus TNFi, with consistent point estimates from the two largest data sources. A numerically greater risk was observed for MACE and serious infection when comparing baricitinib versus TNFi, with different point estimates from the two largest data sources. Findings from this study and their impact on clinical practice should be considered in context of limitations and other evidence regarding the safety and efficacy of baricitinib and other Janus kinase inhibitors. TRIAL REGISTRATION: EU PAS Register ( http://encepp.eu ), identifier #32271.

Association of Physical Activity and Fracture Risk Among Postmenopausal Women.

Importance: Physical activity is inversely associated with hip fracture risk in older women. However, the association of physical activity with fracture at other sites and the role of sedentary behavior remain unclear. Objective: To assess the associations of physical activity and sedentary behavior with fracture incidence among postmenopausal women. Design, Setting, and Participants: The Women's Health Initiative prospective cohort study enrolled 77 206 postmenopausal women aged 50 to 79 years between October 1993 and December 1998 at 40 US clinical centers. Participants were observed for outcomes through September 2015, with data analysis conducted from June 2017 to August 2019. Exposures: Self-reported physical activity and sedentary time. Main Outcomes and Measures: Hazard ratios (HRs) and 95% CIs for total and site-specific fracture incidence. Results: During a mean (SD) follow-up period of 14.0 (5.2) years among 77 206 women (mean [SD] age, 63.4 [7.3] years; 66 072 [85.6%] white), 25 516 (33.1%) reported a first incident fracture. Total physical activity was inversely associated with the multivariable-adjusted risk of hip fracture (>17.7 metabolic equivalent [MET] h/wk vs none: HR, 0.82; 95% CI, 0.72-0.95; P for trend < .001). Inverse associations with hip fracture were also observed for walking (>7.5 MET h/wk vs none: HR, 0.88; 95% CI, 0.78-0.98; P for trend = .01), mild activity (HR, 0.82; 95% CI, 0.73-0.93; P for trend = .003), moderate to vigorous activity (HR, 0.88; 95% CI, 0.81-0.96; P for trend = .002), and yard work (HR, 0.90; 95% CI, 0.82-0.99; P for trend = .04). Total activity was positively associated with knee fracture (>17.7 MET h/wk vs none: HR, 1.26; 95% CI, 1.05-1.50; P for trend = .08). Mild activity was associated with lower risks of clinical vertebral fracture (HR, 0.87; 95% CI, 0.78-0.96; P for trend = .006) and total fractures (HR, 0.91; 95% CI, 0.87-0.94; P for trend < .001). Moderate to vigorous activity was positively associated with wrist or forearm fracture (HR, 1.09; 95% CI, 1.03-1.15; P for trend = .004). After controlling for covariates and total physical activity, sedentary time was positively associated with total fracture risk (>9.5 h/d vs <6.5 h/d: HR, 1.04; 95% CI, 1.01-1.07; P for trend = .01). When analyzed jointly, higher total activity mitigated some of the total fracture risk associated with sedentary behavior. Analysis of time-varying exposures resulted in somewhat stronger associations for total physical activity, whereas those for sedentary time were materially unchanged. Conclusions and Relevance: In older ambulatory women, higher total physical activity was associated with lower total and hip fracture risk but higher knee fracture risk. Mild activity and walking were associated with lower hip fracture risk, a finding with important public health implications because these activities are common in older adults. The positive association between sedentary time and total fracture risk requires further investigation.

Risk factors for 5-year prospective height loss among postmenopausal women.

OBJECTIVE: Height loss is common in older women and has been associated with increased morbidity and mortality. In this study, we identified factors that could predict prospective height loss in postmenopausal women. METHODS: Height was measured in 1,024 postmenopausal women, enrolled in the Buffalo Osteoporosis and Periodontal Disease Study, at baseline and 5 years later using a fixed stadiometer. Demographics, lifestyle, medical history, and medication use were assessed at baseline. Stepwise logistic regression was used to identify factors that are associated with marked height loss of ≥1 inch. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated for each predictor. Receiver-operating characteristic (ROC) curve was performed to determine the discriminatory ability of the prediction model. RESULTS: The mean loss of height was 0.4 (SD 0.7) inches. Age (OR 1.11, 95% CI 1.06-1.16), weight (OR 1.05, 95% CI 1.03-1.07), use of oral corticosteroids (OR 4.96, 95% CI 1.25-19.72), and strenuous exercise at age 18 ≥ three times per week (OR 0.55, 95% CI 0.31-0.98) were significantly associated with marked height loss in the multivariable-adjusted model. The area under the ROC curve is 72.1%. Addition of bone mineral density measures did not improve the discriminatory ability of the prediction model. CONCLUSIONS: This set of available variables may be useful in predicting the 5-year risk of height loss of 1 inch or more in postmenopausal women. These findings may help to target older women at risk of height loss who may benefit most from prevention strategies for fracture and mortality.

Periodontal Disease and Incident Cancer Risk among Postmenopausal Women: Results from the Women's Health Initiative Observational Cohort.

Background: Periodontal pathogens have been isolated from precancerous and cancerous lesions and also shown to promote a procarcinogenic microenvironment. Few studies have examined periodontal disease as a risk factor for total cancer, and none have focused on older women. We examined whether periodontal disease is associated with incident cancer among postmenopausal women in the Women's Health Initiative Observational Study.Methods: Our prospective cohort study comprised 65,869 women, ages 54 to 86 years. Periodontal disease information was obtained via self-report questionnaires administered between 1999 and 2003, whereas ascertainment of cancer outcomes occurred through September 2013, with a maximum follow-up period of 15 years. Physician-adjudicated incident total cancers were the main outcomes and site-specific cancers were secondary outcomes. HRs and 95% confidence intervals (CI) were calculated using Cox proportional hazards regression. All analyses were conducted two-sided.Results: During a mean follow-up of 8.32 years, 7,149 cancers were identified. Periodontal disease history was associated with increased total cancer risk (multivariable-adjusted HR, 1.14; 95% CI, 1.08-1.20); findings were similar in analyses limited to 34,097 never-smokers (HR, 1.12; 95% CI, 1.04-1.22). Associations were observed for breast (HR, 1.13; 95% CI, 1.03-1.23), lung (HR, 1.31; 95% CI, 1.14-1.51), esophagus (HR, 3.28; 95% CI, 1.64-6.53), gallbladder (HR, 1.73; 95% CI, 1.01-2.95), and melanoma skin (HR, 1.23; 95% CI, 1.02-1.48) cancers. Stomach cancer was borderline (HR, 1.58; 95% CI, 0.94-2.67).Conclusions: Periodontal disease increases risk of total cancer among older women, irrespective of smoking, and certain anatomic sites appear to be vulnerable. Impact: Our findings support the need for further understanding of the effect of periodontal disease on cancer outcomes. Cancer Epidemiol Biomarkers Prev; 26(8); 1255-65. ©2017 AACR.

History of Periodontitis Diagnosis and Edentulism as Predictors of Cardiovascular Disease, Stroke, and Mortality in Postmenopausal Women.

BACKGROUND: Few studies have reported associations between periodontitis and cardiovascular disease (CVD) risk in older women, which is the objective of the present investigation. METHODS AND RESULTS: Participants were 57 001 postmenopausal women ages 55 to 89 years (mean 68 years; >85% 60 and older) who were enrolled (1993-1998) in the Women's Health Initiative Observational Study, and were without known CVD when history of periodontitis and edentulism was assessed by questionnaire at study Year-5 (1998-2003). There were 3589 incident CVD events and 3816 total deaths during a mean follow-up of 6.7 years. In multivariable analysis, periodontitis was not associated with CVD events, but was associated with higher total mortality (hazard ratio (HR)=1.12, 95% CI: 1.05-1.21). Edentulism was associated with higher age- and smoking-adjusted risks of CVD (HR=1.42, 95% CI: 1.27-1.59) and mortality (HR=1.47, 95% CI: 1.32-1.63). Further adjustment eliminated the association with CVD, but mortality remained significantly increased (HR=1.17, 95% CI: 1.02-1.33). Stratification on age, race-ethnicity, smoking, and diabetes mellitus yielded comparable results; however, edentulism was more strongly associated with CVD in women reporting ≥1 dental visit (HR=1.57) compared with <1 visit (HR 1.03, interaction P=0.004) annually. CONCLUSIONS: In community-dwelling older women, edentulism was associated with increased risks of CVD and total mortality, and presence of periodontitis, which is more prevalent than edentulism, was associated with 17% higher mortality rate. These findings suggest that improving periodontal condition of the general population could reduce overall mortality.

Inaccurate self-report of height and its impact on misclassification of body mass index in postmenopausal women.

OBJECTIVE: Self-reported height is commonly used in population obesity research. Evidence has also shown a positive association between depression and obesity. We examined the extent of height misreporting and its impact on body mass index (BMI) calculations and classification, and explored whether depression is associated with height misreporting. METHODS: The Buffalo Osteoporosis and Periodontal Disease Follow-up Study enrolled 1,015 postmenopausal women between 2002 and 2006. Participants self-reported their height on a questionnaire before stadiometer measurement at the clinical visit. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale. Odds ratios and 95% CI for association between depression and height misreporting were estimated using logistic regression. RESULTS: Overall, 446 women (43.9%) misreported height by greater than 1/2 inch, of which 296 (29.2%) underestimated and 150 (14.8%) overestimated their height. Height misreporting influenced BMI calculations by ≥1 unit in 12% of women, and influenced classification into WHO BMI categories in 8% of women. After adjusting for age, race, education, and measured BMI, women with significant depressive symptoms were more likely to misreport their height (odds ratio = 1.65, 95% CI, 1.04-2.61). CONCLUSIONS: Height misreporting was common in older women and significantly influenced BMI calculations and classification. Obtaining objective data is thus important for studies investigating obesity-disease associations in this population, especially in those with significant depressive symptoms.

Vitamin D Status and Tooth Loss in Postmenopausal Females: The Buffalo Osteoporosis and Periodontal Disease (OsteoPerio) Study.

BACKGROUND: Vitamin D is hypothesized to reduce risk for tooth loss via its influence on bone health, inflammation, and the immune response. The association between plasma 25-hydroxyvitamin D [25(OH)D] concentrations and prevalence and 5-year incidence of tooth loss in a cohort of postmenopausal females was examined. METHODS: Participants underwent oral examinations at study baseline (1997 to 2000) and follow-up (2002 to 2005) to determine the number of missing teeth and 5-year incidence of tooth loss, respectively. At both visits, females self-reported reasons for each missing tooth. At baseline, 152 females reported no history of tooth loss, and 628 were categorized as reporting a history of tooth loss as a result of periodontal disease (n = 70) or caries (n = 558) (total n = 780). At follow-up, 96, 376, 48, and 328 females were categorized into the aforementioned categories related to tooth loss (total n = 472). Logistic regression was used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for tooth loss by category of baseline 25(OH)D (nmol/L) concentrations. Models were adjusted for age, income, smoking status, frequency of dental visits, waist circumference, and recreational physical activity. P value for trend was estimated using continuous concentrations of 25(OH)D. RESULTS: Among females with 25(OH)D ≥50 (adequate vitamin D status) compared to <50 nmol/L (deficient/inadequate), the adjusted ORs were 1.24 (95% CI = 0.82 to 1.87), P-trend = <0.05 for the history (prevalence) of tooth loss resulting from periodontal disease or caries and 1.07 (95% CI = 0.62 to 1.85), P-trend = 0.11 for the incidence of tooth loss resulting from periodontal disease or caries. No statistically significant association was observed between 25(OH)D and the history or incidence of tooth loss caused by periodontal disease. An increased odds of the history of tooth loss attributable to caries was observed with increasing concentrations of 25(OH)D (P-trend = <0.05) but was not confirmed in prospective analyses. CONCLUSION: In this cohort of postmenopausal females, the data do not support an association between vitamin D status and tooth loss.

Periodontal Pathogens and Risk of Incident Cancer in Postmenopausal Females: The Buffalo OsteoPerio Study.

BACKGROUND: Extraoral translocation of oral bacteria may contribute to associations between periodontal disease and cancer. The associations among the presence of three orange-complex periodontal pathogens (Fusobacterium nucleatum, Prevotella intermedia, and Campylobacter rectus), two red-complex periodontal pathogens (Porphyromonas gingivalis and Tannerella forsythia), and cancer risk were investigated. METHODS: A total of 1,252 postmenopausal females enrolled in the Buffalo Osteoporosis and Periodontal Disease Study were followed prospectively. Baseline subgingival plaque samples were assessed for the presence of periodontal pathogens using indirect immunofluorescence. Incident cancer cases were adjudicated by staff physicians via review of medical records. Cox proportional hazards regression was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations of periodontal pathogens with total cancer and site-specific cancer risk in unadjusted and multivariable-adjusted models. RESULTS: Neither the presence of individual pathogens nor the presence of any red-complex pathogens was associated with total cancer or site-specific cancers. Borderline associations were seen among the presence of any orange-complex pathogens (F. nucleatum, P. intermedia, and C. rectus), total cancer risk (HR = 1.35, 95% CI = 1.00 to 1.84), and lung cancer risk (HR = 3.02, 95% CI = 0.98 to 9.29). CONCLUSIONS: No associations were found between the presence of individual subgingival pathogens and cancer risk. However, there were suggestions of borderline positive associations of the presence of any orange-complex pathogens with total cancer and lung cancer risk. The study is limited by the small number of cancer cases and the assessment of only five oral bacteria. Additional research is needed to understand the possible role of periodontal disease in carcinogenesis.

Periodontal disease severity and cancer risk in postmenopausal women: the Buffalo OsteoPerio Study.

PURPOSE: Few prospective studies have reported on relationships between objective periodontal disease (PD) measures and cancer risk. This association was examined in 1,337 postmenopausal women participating in the Buffalo OsteoPerio Study. METHODS: Oral alveolar crestal height (ACH) was measured using oral radiographs. Incident cancers were adjudicated with medical records. Hazard ratios (HRs) and 95 % confidence intervals (CIs) for associations between ACH and incident cancer outcomes were estimated using Cox proportional hazards models. RESULTS: There were 203 confirmed total incident cancer cases during follow-up (12.2 ± 4.2 years). After adjusting for age and smoking, there were no statistically significant associations between ACH-defined PD categories and total cancer risk (mild/moderate vs. none: HR 1.33, 95 % CI 0.91-1.94; severe vs. none: HR 1.20, 95 % CI 0.77-1.86). ACH-defined PD categories were not associated with common site-specific cancers. Whole-mouth mean and worst-site ACH (per 1 mm loss) were significantly associated with increased risk of lung (adjusted HR 1.81, 95 % CI 1.30-2.54; adjusted HR 1.34, 95 % CI 1.08-1.66, respectively), but not total or other site-specific cancer. Smoking status modified the associations between continuous ACH variables and total cancer risk; measures of PD were associated with total cancer among smokers but not never smokers (interaction p = 0.02 and p < 0.01 for whole-mouth mean and worst-site ACH, respectively). CONCLUSIONS: ACH-defined PD was associated with total cancer risk in ever but not never smoking postmenopausal women. Whole-mouth mean and worst-site ACH were associated with increased lung cancer risk. However, these results need to be interpreted cautiously given the small number of lung cancer cases (n = 18). Further research utilizing a larger sample is warranted to confirm the relationships among oral bone loss, site-specific cancers, and total cancer.

Periodontal Disease and Breast Cancer: Prospective Cohort Study of Postmenopausal Women.

BACKGROUND: Periodontal disease has been consistently associated with chronic disease; there are no large studies of breast cancer, although oral-associated microbes are present in breast tumors. METHODS: In the Women's Health Initiative Observational Study, a prospective cohort of postmenopausal women, 73,737 women without previous breast cancer were followed. Incident, primary, invasive breast tumors were verified by physician adjudication. Periodontal disease was by self-report. HRs and 95% confidence intervals (CI) were estimated by Cox proportional hazards, adjusted for breast cancer risk factors. Because the oral microbiome of those with periodontal disease differs with smoking status, we examined associations stratified by smoking. RESULTS: 2,124 incident, invasive breast cancer cases were identified after mean follow-up of 6.7 years. Periodontal disease, reported by 26.1% of women, was associated with increased breast cancer risk (HR 1.14; 95% CI, 1.03-1.26), particularly among former smokers who quit within 20 years (HR 1.36; 95% CI, 1.05-1.77). Among current smokers, the trend was similar (HR 1.32; 95% CI, 0.83-2.11); there were few cases (n = 74) and the CI included the null. The population attributable fraction was 12.06% (95% CI, 1.12-21.79) and 10.90% (95% CI, 10.31-28.94) for periodontal disease among former smokers quitting within 20 years and current smokers, respectively. CONCLUSION: Periodontal disease, a common chronic inflammatory disorder, was associated with increased risk of postmenopausal breast cancer, particularly among former smokers who quit in the past 20 years. IMPACT: Understanding a possible role of the oral microbiome in breast carcinogenesis could impact prevention.

Association of serum 17ß-estradiol concentration, hormone therapy, and alveolar crest height in postmenopausal women.

BACKGROUND: Declines in endogenous estrogen levels after menopause can lead to systemic bone loss, including loss of oral bone and alveolar crest height (ACH). However, few studies have assessed both serum 17ß-estradiol (E2) and exogenous hormone therapy (HT) use in relation to oral bone loss. METHODS: This study examines the associations among serum E2, HT use, and ACH in 613 postmenopausal women from the Buffalo OsteoPerio study. Baseline ACH levels and 5-year ACH were assessed for groups according to E2 level (undetectable, >5.00 to ≤18.00, >18.00 to ≤46.07, and >46.07 pg/mL) and among HT use (never, ever) using analysis of variance and analysis of covariance. Logistic regression was used to analyze the association of ACH loss with serum E2 and HT use. RESULTS: In cross-sectional analyses, no association was found of serum E2 with whole-mouth mean or worst-site ACH. However, history of HT use was associated with ACH. Women who had never used HT had more ACH loss assessed as a whole-mouth mean ACH (P = 0.01) and as worst-site ACH loss (P = 0.03). In logistic regression analyses of baseline ACH loss severity, HT never-users had two-fold higher odds of being in the severe ACH loss category compared to ever-users (odds ratio, 2.00; 95% confidence interval, 1.11 to 3.62). No association was observed of 5-year change in ACH with baseline serum E2 or HT use. CONCLUSION: Although this study did not detect an association with current serum E2 level and ACH, HT use was found to be associated with less ACH loss in postmenopausal women.

History of periodontal disease diagnosis and lung cancer incidence in the Women's Health Initiative Observational Study.

PURPOSE: While some evidence suggests that periodontal disease (PD) might be positively associated with lung cancer, prospective studies in women are limited. Previous findings may reflect residual confounding by smoking. The study aims to determine whether history of PD diagnosis is associated with incident lung cancer in a large cohort of postmenopausal women. METHODS: Prospective analyses were conducted in a cohort of 77,485 postmenopausal women enrolled in the Women's Health Initiative Observational Study. History of PD (prevalence of 26.1 %) was self-reported, and 754 incident lung cancer cases occurred during an average 6.8 (SD ± 2.6) years of follow-up. Cox proportional hazards regression analysis was used to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs). RESULTS: Overall, PD was positively associated with lung cancer risk after adjusting for detailed smoking history including smoking status and pack-years of smoking (HR 1.24, 95 % CI 1.07-1.45). There was a positive additive interaction between PD with pack-years of smoking (p = 0.02), suggesting a potential synergistic effect between PD and smoking intensity on lung cancer. The association between PD and lung cancer was stronger in former smokers. When restricted to never-smokers, PD was not associated with lung cancer (HR 1.02, 95 % CI 0.68-1.53). CONCLUSIONS: Periodontal disease was not independently associated with lung cancer in non-smoking postmenopausal women. However, smoking and PD jointly increased lung cancer risk beyond that expected from the sum of the each effect separately. The potential synergism between PD and smoking on lung cancer warrants further examination.

Associations between smoking and tooth loss according to the reason for tooth loss: the Buffalo OsteoPerio Study.

BACKGROUND: Smoking is associated with tooth loss. However, smoking's relationship to the specific reason for tooth loss in postmenopausal women is unknown. METHODS: Postmenopausal women (n = 1,106) who joined a Women's Health Initiative ancillary study (The Buffalo OsteoPerio Study) underwent oral examinations for assessment of the number of missing teeth, and they reported the reasons for tooth loss. The authors obtained information about smoking status via a self-administered questionnaire. The authors calculated odds ratios (ORs) and 95 percent confidence intervals (CIs) by means of logistic regression to assess smoking's association with overall tooth loss, as well as with tooth loss due to periodontal disease (PD) and with tooth loss due to caries. RESULTS: After adjusting for age, education, income, body mass index, history of diabetes diagnosis, calcium supplement use and dental visit frequency, the authors found that heavy smokers (≥ 26 pack-years) were significantly more likely to report having experienced tooth loss compared with never smokers (OR = 1.82; 95 percent CI, 1.10-3.00). Smoking status, packs smoked per day, years of smoking, pack-years and years since quitting smoking were significantly associated with tooth loss due to PD. For pack-years, the association for heavy smokers compared with that for never smokers was OR = 6.83 (95 percent CI, 3.40 -13.72). The study results showed no significant associations between smoking and tooth loss due to caries. CONCLUSIONS AND PRACTICAL IMPLICATIONS: Smoking may be a major factor in tooth loss due to PD. However, smoking appears to be a less important factor in tooth loss due to caries. Further study is needed to explore the etiologies by which smoking is associated with different types of tooth loss. Dentists should counsel their patients about the impact of smoking on oral health, including the risk of experiencing tooth loss due to PD.

A cross-sectional survey of nonspecific low back pain among 2083 schoolchildren in China.

STUDY DESIGN: A cross-sectional survey of 2083 schoolchildren. OBJECTIVE: To investigate the prevalence of nonspecific low back pain (LBP) among schoolchildren aged between 10 and 18 years in China. SUMMARY OF BACKGROUND DATA: LBP have been a serious health problem in schoolchildren. On the basis of literature, the lifetime occurrence of nonspecific LBP in children and adolescents varies between 7% and 72%, but little is known about LBP among this demographic group in China. METHODS: Schoolchildren aged 10 to 18 years were sampled from two grades in an elementary school and four grades in a secondary school. Participants were asked to fill in a questionnaire on LBP. The questionnaire addressed demographic items, anthropometric factors and characteristics of nonspecific LBP, such as frequency, duration, nature, pain scale. Nonspecific LBP is defined as the pain in the back from the 12th ribs to the buttock area without organic factors. A total of 2235 questionnaires were distributed, of which 2100 were answered, a response rate of 93.7%. Among those answers, 2083 (977 from male students and 1106 from female students) provided measurable data. RESULTS: The occurrence of nonspecific LBP was high, with 29.1% students suffering from this condition in the past 3 months (24.7% in boys, 33.1% in girls). In addition, an increased occurrence was observed with age. The occurrences of LBP in 10 to 14 years and 15 to 18 years were 21.5% and 38.2%, respectively. In several aspects of LBP, statistically significant differences were observed between boys and girls, including the frequency of the pain (P = 0.003), the nature of the pain (P = 0.000), the likelihood of seeking for medical assistance (P = 0.007), the impact on normal daily life (P = 0.016), and the occurrence of LBP after bending over the desk for a period of time (P = 0.024). Female students had more frequent LBP and were less willing to see a physician. In addition, more female students (45/366) had LBP accompanied with radiating pain than male students (20/241). CONCLUSION: There is a high prevalence of LBP in Chinese schoolchildren. The occurrence of LBP increases with age in both sexes. LBP is significantly more prevalent in girls.