Xiaoping Weng

Kaiser Permanente, Oakland, California, United States

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Publications (9)48.97 Total impact

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    ABSTRACT: The objective of this study was to assess inflammatory bowel disease (IBD) medications in relation to lymphoma risk. Information on IBD and relevant medications and other utilization was obtained from the Kaiser Permanente IBD Registry, 1996-2009. Lymphoma cases were ascertained from the Kaiser Permanente Cancer Registry. Lymphoma incidence was compared between the IBD cohort and the general Kaiser Permanente population. Of the 16,023 IBD patients without human immunodeficiency virus followed an average 5.8 years, 43 developed lymphoma. IBD patients with and without lymphoma did not differ with respect to past IBD-related visits, procedures, or tests. The standardized incidence rate ratio (SIRR) for lymphoma among IBD patients with no dispensing of thiopurine or anti-tumor necrosis factor (TNF) was 1.0 (95% confidence interval (CI): 0.96-1.1). Of the 21,282 person-years involving exposure to thiopurine or anti-TNF, 81% involved thiopurine alone; 3%, anti-TNF alone; and 16%, combination therapy. Among patients with thiopurine but not anti-TNF dispensings, the SIRR was 0.3 (95% CI: 0.2-0.4) for past use and 1.4 for current use (95% CI: 1.2-2.7). Among patients with dispensing of anti-TNF (with and without thiopurine), the SIRR was 5.5 for past use (95% CI: 4.5-6.6) and 4.4 for current use (95% CI: 3.4-5.4). The most common lymphoma subtypes were diffuse large B-cell lymphoma (44%), follicular lymphoma (14%), and Hodgkin's disease (12%). Our study provides evidence that IBD alone is not associated with the risk of lymphoma. Use of anti-TNF with thiopurine and current use of thiopurine alone were associated with increased risk, although the effect of disease severity merits further evaluation.
    The American Journal of Gastroenterology 12/2011; 106(12):2146-53. · 9.21 Impact Factor
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    ABSTRACT: The adverse effect of bisphenol-A (BPA) on the male reproductive system observed in animal studies has not been well examined in human populations. BPA is potentially a serious public health problem because of its widely detected presence in the human body. This study was conducted among 427 male workers in regions where high levels of BPA exposure existed. All participants provided urine samples, which were tested for BPA concentration using high-performance liquid chromatography. Male sexual dysfunction was ascertained using standard male sexual function inventories. Male sexual dysfunction was measured in 4 domains using 7 indices. After controlling for potential confounders using linear regression, increasing urine BPA level was associated with worsening male sexual function on a continuous scale. All 7 indices demonstrated this negative linear correlation. Increasing urine BPA level was associated with decreased sexual desire (P < .001), more difficulty having an erection (P < .001), lower ejaculation strength (P < .001), and lower level of overall satisfaction with sex life (P < .01). A similar negative correlation was also observed among participants exposed to BPA from only environmental sources (no occupational exposure to BPA), although the estimates in this group were less stable because of a smaller sample size. Our results reveal a correlation between a biological measure of urine BPA level and declining male sexual function. This finding may enhance the understanding of the BPA effect in human populations, and may have important public health implications given the widespread human exposure to BPA.
    Journal of Andrology 05/2010; 31(5):500-6. · 3.37 Impact Factor
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    ABSTRACT: Animal studies have suggested that bisphenol-A (BPA) is a potential human endocrine disrupter; but evidence from human studies is needed. We conducted an occupational cohort study to examine the effect of occupational exposure to BPA on the risk of male sexual dysfunction. Current workers from BPA-exposed and control factories were recruited. The exposed workers were exposed to very high BPA levels in their workplace. Male sexual function was ascertained through in-person interviews using a standard male sexual function inventory. BPA-exposed workers had consistently higher risk of male sexual dysfunction across all domains of male sexual function than the unexposed workers. After controlling for matching variables and potential confounders, exposed workers had a significantly increased risk of reduced sexual desire [odds ratios (OR) = 3.9, 95% confidence interval: 1.8-8.6), erectile difficulty (OR = 4.5, 95% CI 2.1-9.8), ejaculation difficulty (OR = 7.1, 95% CI 2.9-17.6), and reduced satisfaction with sex life (OR = 3.9, 95% CI 2.3-6.6). A dose-response relationship was observed with an increasing level of cumulative BPA exposure associated with a higher risk of sexual dysfunction. Furthermore, compared with the unexposed workers, BPA-exposed workers reported significantly higher frequencies of reduced sexual function within 1 year of employment in the BPA-exposed factories. Our findings provide the first evidence that exposure to BPA in the workplace could have an adverse effect on male sexual dysfunction.
    Human Reproduction 11/2009; 25(2):519-27. · 4.67 Impact Factor
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    ABSTRACT: We conducted a population-based case-control study among healthy sperm donors to study exposure to magnetic fields (MFs) and poor sperm quality. All participants wore a meter to capture daily MF exposure. After controlling for confounders, compared to those with lower MF exposure, those whose 90th percentile MF level > or = 1.6mG had a two-fold increased risk of abnormal sperm motility and morphology (odds ratio (OR): 2.0, 95% confidence interval (CI): 1.0-3.9). Increasing duration of MF exposure above 1.6 mG further increased the risk (p=0.03 for trend test). Importantly, the association and dose-response relationship were strengthened when restricted to those whose measurement day reflected their typical day of the previous 3 months (a likely period of spermatogenesis). Age-adjusted Spearman Rank Order Correlations showed an inverse correlation between MF exposure and all semen parameters. Our study provides some evidence for the first time that MF exposure may have an adverse effect on sperm quality.
    Reproductive Toxicology 10/2009; 29(1):86-92. · 3.14 Impact Factor
  • Epidemiology. 01/2009; 20.
  • Article: Reply.
    De-Kun Li, Xiaoping Weng, Roxana Odouli
    American journal of obstetrics and gynecology 08/2008; · 3.28 Impact Factor
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    Xiaoping Weng, Roxana Odouli, De-Kun Li
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    ABSTRACT: The objective of the study was to examine whether the risk of miscarriage is associated with caffeine consumption during pregnancy after controlling for pregnancy-related symptoms. This was a population-based prospective cohort study. An increasing dose of daily caffeine intake during pregnancy was associated with an increased risk of miscarriage, compared with no caffeine intake, with an adjusted hazard ratio (aHR) of 1.42 (95% confidence interval 0.93 to 2.15) for caffeine intake of less than 200 mg/day, and aHR of 2.23 (1.34 to 3.69) for intake of 200 or more mg/day, respectively. Nausea or vomiting during pregnancy did not materially affect this observed association, nor did the change in intake pattern of caffeine during pregnancy. In addition, the magnitude of the association appeared to be stronger among women without a history of miscarriage (aHR 2.33, 1.48 to 3.67) than that among women with such a history (aHR 0.81, 0.34 to 1.94). Our results demonstrated that high doses of caffeine intake during pregnancy increase the risk of miscarriage, independent of pregnancy-related symptoms.
    American journal of obstetrics and gynecology 04/2008; 198(3):279.e1-8. · 3.28 Impact Factor
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    ABSTRACT: Most previous population-based studies of mortality in inflammatory bowel disease (IBD) did not account for medication use. We evaluated mortality by IBD medication use among members of the Kaiser Permanente Northern California IBD Registry. The retrospective, population-based cohort study included 9032 persons who received at least one inpatient or 2 outpatient diagnoses of IBD during 1996-2002. Age and sex standardized mortality ratios measured the associations between IBD and all-cause and cause-specific mortality. Age, sex, and smoking adjusted odds ratios measured the association of mortality by IBD medication use. Compared with health plan members without IBD, mortality was increased in patients with Crohn's disease (CD) (1.4; 95% confidence interval, 1.2-1.6) but not ulcerative colitis (UC) (1.0; 95% CI, 0.9-1.2). CD was associated with increased mortality from infectious and parasitic diseases (4.1; 95% CI, 1.7-8.5), septicemia (6.8; 95% CI, 2.2-15.8), small intestinal cancer (48.1; 95% CI, 5.8-17.4), respiratory diseases (1.9; 95% CI, 1.3-2.7), digestive diseases other than IBD (2.4; 95% CI, 1.0-4.8), and liver diseases (2.6; 95% CI, 1.0-5.3). UC was associated with increased mortality from digestive diseases other than IBD (3.9; 95% CI, 2.4-6.0). The relationship with CD mortality was 0.7 for aminosalicylates (95% CI, 0.5-1.1), 1.3 (95% CI, 0.9-1.9) for immunomodulators, and 1.0 (95% CI, 0.7-1.4) for corticosteroids. Among patients with UC, these odds ratios were 0.8 (95% CI, 0.5-1.1) for aminosalicylates, 0.5 (95% CI, 0.3-0.9) for immunomodulators, and 0.8 (95% CI, 0.6-1.1) for corticosteroids. Mortality is increased in CD. Infections, respiratory diseases, and digestive diseases are important specific causes of death. IBD medication use has varying associations with mortality.
    Gastroenterology 12/2007; 133(6):1779-86. · 12.82 Impact Factor
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    ABSTRACT: Previous studies provide evidence that some immune-mediated diseases occur at greater frequency among inflammatory bowel disease (IBD) patients than in the general population. The present study examined the co-occurrence of IBD with common immune-mediated disorders including asthma, psoriasis, type 1 diabetes, rheumatoid arthritis, multiple sclerosis, systemic lupus erythematosus, vitiligo, autoimmune thyroiditis (Grave's and Hashimoto's), and chronic glomerulonephritis. We conducted a cross-sectional study among members of the Kaiser Permanente Medical Care Program for the period 1996-2005. A total of 12,601 patients with at least two IBD diagnoses in computerized visit data were ascertained. Four persons without IBD were matched to each IBD patient on age, gender, and length of enrollment. Information on co-occurring diseases was obtained from computerized visit data for 1996-2005. Conditional logistic regression was used to estimate the odds ratio and 95% confidence interval for the association of IBD with immune-mediated disorders after adjusting for smoking. Seventeen percent of the IBD patients and 10% of the persons without IBD had a diagnosis for at least one immune-mediated disease. IBD patients were more likely to have asthma (1.5, 95% CI 1.4-1.6), psoriasis (1.7, 95% CI 1.5-2.0), rheumatoid arthritis (1.9, 95% CI 1.5-2.3), and multiple sclerosis (2.3, 95% CI 1.6-3.3). Among the immune-mediated diseases we studied, most were more common in IBD patients than in persons without IBD, suggesting that IBD shares common etiologic factors with other immune-mediated diseases.
    The American Journal of Gastroenterology 08/2007; 102(7):1429-35. · 9.21 Impact Factor