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Biomedical subjects

B McKnight

Publications and source records attributed to B McKnight.

At least 37 records · Page 2Linked to original sources
PubMed1998

Risk of endometrial cancer in relation to use of low-dose, unopposed estrogens.

OBJECTIVE: To determine whether a low dosage (0.3 mg/day) of unopposed conjugated estrogens can be used without incurring an elevated risk of endometrial cancer. METHODS: In this case-control study, cases (n = 484) consisted of women diagnosed with endometrial cancer between 1985 and 1991 in three counties in Western Washington. Controls (n = 780) were identified using random digit dialing within the same three counties. Subjects were interviewed in person to obtain basic demographic and medical history information, as well as specific information about hormone use. RESULTS: Eighteen cases and eight controls had taken 0.3 mg/day of unopposed conjugated estrogens and no other dose or preparation of estrogens (risk relative to that of women who had not taken postmenopausal hormones = 5.4, 95% confidence interval [CI] 2.3, 13.0). The risk was particularly high in women whose use of this dose was both current and of more than 8 years' duration (odds ratio = 9.2, 95% CI 2.9, 29.0). The elevation in risk in users of 0.3 mg/day was similar in size to that associated with the daily unopposed use of 0.625 mg of conjugated estrogens. CONCLUSION: The results suggest that a dosage of 0.3 mg per day of unopposed conjugated estrogens is associated with an increased risk of endometrial cancer.

Aged↗
PubMed1998

Risk factors for incident and recurrent condylomata acuminata among men. A population-based study.

BACKGROUND AND OBJECTIVES: The rapid increase in the number of physician office visits for condylomata acuminata and the association of human papillomavirus and cancer has prompted renewed interest in the epidemiology of this sexually-transmitted disease. Few epidemiologic studies have examined what risk factors are associated with condylomata acuminata in men. GOAL: To determine what factors may predispose a man to the occurrence of condylomata acuminata. STUDY DESIGN: A population-based case-control study was conducted among male members of a health maintenance organization. Patients were men 18 years or older who were seen for condyloma at one of four primary care clinics of Group Health Cooperative of Puget Sound between April 1, 1987 and September 30, 1991. Control subjects were frequency matched to the patients on clinic site, race, and age. In-person interviews were used to ascertain exposure histories from both patients and control subjects. RESULTS: Recurrent condyloma was reported by about one third of our patients. Patients with multiple partners were strongly associated with developing the disease. Several factors were either more strongly or only associated with recurrent disease. Other behavioral measures, such as recreational drug use, were also related the occurrence of condyloma. CONCLUSION: These results confirm the sexual-transmitted mechanism of condyloma in men. Exposure to multiple partners was associated with elevated risk of both recurrent and incident disease. Other cofactors may be involved in the etiology of condyloma.

Adolescent↗
PubMed1998

Risk factors for incident and recurrent condylomata acuminata among women. A population-based study.

BACKGROUND: Condylomata acuminata is one of the most common sexually transmitted diseases (STDs) diagnosed in the United States, yet relatively little research has been conducted on the determinants of this disease in well-defined populations. GOAL: To determine the exposures that predispose a woman to the development of condylomata acuminata or genital warts. STUDY DESIGN: A population-based case-control study was conducted among enrollees of Group Health Cooperative of Puget Sound. Patients (94 women with incident and 55 women with recurrent condyloma) were diagnosed between April 1, 1987 and September 30, 1991. Control subjects were 133 women without a history of genital warts. An in-person interview was conducted to collect information on subject characteristics, exposures, and on all episodes of genital warts. RESULTS: Women with five or more partners within the 5 years before reference date were over seven times more likely to have incident condyloma (relative risk [RR], 7.5; 95% confidence interval [CI], 3.1-18.1) and over 12 times more likely to have recurrent condyloma (RR, 12.8; 95% CI, 4.2-38.9) compared with women with only one sexual partner during this time period. An increased risk of incident condyloma was also associated with a history of any STD (RR, 2.6; 95% CI, 1.1-5.8), a history of oral herpes (RR, 2.2; 95% CI, 1.1-4.4), and a history of allergies (RR, 2.0 95% CI, 1.0-3.8). Our data did not support a strong association between risk of condyloma and smoking or recent use of oral contraceptives. CONCLUSION: Our results suggest that risk of condyloma is primarily related to sexual behavior. We did not observe a strong association between risk of condyloma and many of the exposures considered to be potential cofactors for anogenital cancers associated with other types of human papillomaviruses.

Adolescent↗
PubMed1998

Likelihood-based inference for the genetic relative risk based on affected-sibling-pair marker data.

Using genetic marker data from affected sibling pairs, we study likelihood-based linkage analysis under quasi-recessive, quasi-dominant, and general single-locus models. We use an epidemiologic parameterization under a model where the marker locus is closely linked to the putative disease susceptibility gene. This model and parameterization allow inferences about the relative risk associated with the susceptible genotype. We base inferences on approximate likelihoods that focus on the affected siblings in the sibship and, using these likelihoods, we derive closed-form maximum likelihood estimators for model parameters and closed-form likelihood ratio statistics for tests that the relative risk associated with the susceptible genotype is one. Under the general single-locus model, our likelihood ratio test is the same as the iteratively computed triangle test proposed by Holmans (1993, American Journal of Human Genetics 52, 362-374) for the case where marker identity-by-descent is known; our derivation gives a closed form for the test statistic. We present quartiles of the distribution of parameter estimates and critical values for the exact null distribution of our likelihood ratio test statistics; we also give large-sample approximations to their null distributions. We show that the powers of our likelihood ratio tests exceed the powers of more commonly used nonparametric affected-sibling-pair tests when the data meet the inheritance model assumptions used to derive the test; we also show that our tests' powers are robust to violation of model assumptions. We conclude that our model-based inferences provide a practical alternative to more common affected-sibling-pair tests when investigators have some knowledge about the mode of inheritance of a disease and that our methods may sometimes be useful for comparing the genetic relative risk with environmental relative risks.

Disease Susceptibility↗
PubMed1997

Cofactors with human papillomavirus in a population-based study of vulvar cancer.

BACKGROUND: Human papillomavirus (HPV) has been previously associated with vulvar cancer. In a population-based study, we examined whether exposure to HPV, cigarette smoking, or herpes simplex virus 2 (HSV2) increases the risk of this cancer. METHODS: Incident cases of in situ (n = 400) and invasive (n = 110) squamous cell vulvar cancer diagnosed among women living in the Seattle area from 1980 through 1994 were identified. Serum samples were analyzed for antibodies against specific HPV types and HSV2. HPV DNA in tumor tissue was detected by means of the polymerase chain reaction. In most analyses, case subjects were compared with population-based control subjects (n = 1403). Relative risks of developing vulvar cancer were estimated by use of adjusted odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Increased risks of in situ or invasive vulvar cancer were associated with HPV16 seropositivity (ORs = 3.6 [95% CI = 2.6-4.8] and 2.8 [95% CI = 1.7-4.7], respectively), current cigarette smoking (ORs = 6.4 [95% CI = 4.4-9.3] and 3.0 [95% CI = 1.7-5.3], respectively), and HSV2 seropositivity (ORs = 1.9 [95% CI = 1.4-2.6] and 1.5 [95% CI = 0.9-2.6], respectively). When the analysis was restricted to HPV16 DNA-positive tumors (in situ or invasive), the OR associated with HPV16 seropositivity was 4.5 (95% CI = 3.0-6.8). The OR for vulvar cancer was 18.8 (95% CI = 11.9-29.8) among current smokers who were HPV16 seropositive in comparison with never smokers who were HPV16 seronegative. CONCLUSIONS: Current smoking, infection with HPV16, and infection with HSV2 are risk factors for vulvar cancer. Risk appears particularly strong among women who are both current smokers and HPV16 seropositive.

Adult↗
PubMed1997

A study of reproductive function in patients with seminoma treated with radiotherapy and orchidectomy: (SWOG-8711). Southwest Oncology Group.

PURPOSE: The results of Southwest Oncology Group Study 8711 (Group 2B) are presented. The objective was to evaluate the natural history of sperm concentration and selected hormonal parameters in patients with testicular cancer treated with orchiectomy and radiotherapy. METHODS AND MATERIALS: Of a total of 207 patients enrolled on SWOG 8711, 53 pure seminoma patients were identified who were treated with orchiectomy and radiotherapy only. Sperm concentration, follicle-stimulating hormone (FSH) levels, and sexual satisfaction scores were the main parameters followed. RESULTS: A fraction of the patients were infertile prior to receiving radiotherapy. Our analysis indicates that incidental radiation dose to the remaining testicle affects time to recovery of fertility, and at an aggregate level, changes in FSH mirror changes in sperm concentration over time. This phenomenon is the same as that described in patients free from testicular cancer. These men evaluated their sexual activity as good after orchidectomy. CONCLUSION: Our data support the use of clamshell-type testicular shields as a means of providing maximum protection to the remaining testicle.

Adult↗
PubMed1997

Risk of endometrial cancer in relation to use of oestrogen combined with cyclic progestagen therapy in postmenopausal women.

BACKGROUND: Postmenopausal oestrogen therapy reduces the risk of osteoporosis and cardiovascular diseases but is associated with an increased risk of endometrial cancer. We have assessed the impact of a regimen of oestrogen with cyclic progestagen on risk of endometrial cancer for postmenopausal women. METHODS: We did a population-based case-control study of women aged 45-74 years in western Washington State, USA. Cases were identified from a regional cancer registry as having histologically confirmed endometrial cancer during 1985-91. 832 (72%) of 1154 eligible cases completed interviews. Controls were identified by random digit dialling, screened for intact uterus, frequency matched for age and county, and randomly assigned a reference date within 1985-91. Interviews with 1114 (73%) of 1526 eligible controls were done. The women provided information about use of hormone replacement therapy, and reproductive and medical history before diagnosis date (cases) or reference date (controls). FINDINGS: Relative to women who had never used hormones (for > 6 months), women who had taken unopposed oestrogen had a four-fold increase (95% CI 3.1-5.1) in risk of endometrial cancer. Women who used a combined therapy of oestrogen with cyclic progestagen (eg. medroxyprogesterone acetate) had a relative risk of 14 (1.0-1.9). Among women with fewer than 10 days of added progestagen per month, the relative risk was 3.1 (1.7-5.7). Whereas that for women with 10-21 days of added progestagen was 1.3 (0.8-2.2). The use of these combined regimens for 5 or more years was associated with risks of 3.7 (1.7-8.2) and 2.5 (1.1-5.5), respectively, relative to non-users of hormones. INTERPRETATION: Postmenopausal women who use combined therapy of oestrogen with cyclic progestagen on a long-term basis have an increased risk of endometrial cancer compared with those who are not on hormone replacement, even when progestagen is added for 10 or more days per month. This increase is much smaller than that associated with unopposed oestrogen, but needs to be confirmed.

Aged↗
PubMed1997

Estrogen replacement therapy and prognosis after first myocardial infarction.

The effects of estrogen replacement therapy on prognosis in women with established coronary disease remain uncertain. The authors conducted a retrospective cohort study of 726 women (mean age, 66.2 years) who survived first myocardial infarction to hospital discharge from 1980 through 1991, while enrolled at Group Health Cooperative of Puget Sound in western Washington State. Estrogen replacement therapy after myocardial infarction (122 women) was ascertained from computerized pharmacy records. Reinfarctions (n = 135) and deaths (n = 183) through 1993 were identified, and relative risks were calculated. The relative risk for reinfarction associated with current estrogen replacement therapy after myocardial infarction, adjusting for age and time since infarction, was 0.64 (95% confidence interval (CI) 0.32-1.30), and that for past estrogen replacement therapy was 0.90 (95% CI 0.62-1.31). The relative risk for all-cause mortality associated with current estrogen replacement therapy was 0.50 (95% CI 0.25-1.00), and that for past estrogen replacement therapy was 0.79 (95% CI 0.56-1.09). While estrogen users were less likely than nonusers to have a history of diabetes or congestive heart failure, adjustment for these and additional prognostic factors altered risk estimates only slightly. Estrogen replacement therapy after first myocardial infarction was not associated with increased risk of reinfarction or mortality. This study provides reassurance regarding the safety of estrogen replacement therapy after myocardial infarction in women.

Adult↗
PubMed1997

Estimating the risk of breast cancer in relation to the interval since last term pregnancy.

We review the analytical methods of studies that asked whether a term pregnancy transiently increases a woman's risk of breast cancer. These analyses must separate the possible influence of a recent pregnancy from that of two other correlated variables, attained age and age at last pregnancy. Most analyses have compared women of the same parity. To determine, however, whether the risk of breast cancer is different than it would have been had the last pregnancy never occurred, it is necessary to compare the risk of breast cancer over time among women of parity N+1 with women of parity N, which has been done in a few studies. To generate relative risk estimates that are independent of arbitrary coding decisions, we show that the analytical models must be more complex than those in published studies. We used these models to compare women of parity N and N+1 for breast cancer occurrence, using data from the U.S. Cancer and Steroid Hormone Study. For the first 6 years after delivery, first term pregnancy was associated with lower or unchanged risk of breast cancer, second pregnancy with higher risk, third pregnancy with lower risk, and fourth pregnancy with both lower and higher risk depending on age at delivery. Given the inconsistent findings between adjoining levels of parity and the wide confidence intervals around the estimates, we could not find clear evidence for or against the theory that term pregnancy is transiently associated with an increased risk of breast cancer.

Adult↗
PubMed1996

Vasectomy and prostate cancer: a case-control study in a health maintenance organization.

A case-control study was conducted within Group Health Cooperative of Puget Sound to evaluate the relation between prior vasectomy and the risk of prostate cancer. Cases consisted of 175 men newly diagnosed with histologically confirmed prostate cancer during 1989-1991. A total of 258 controls, matched to cases on birth year and membership status, were randomly selected from the general membership of the plan. Information was collected from mailed questionnaires and medical records on medical history, including prior vasectomy, anthropometric measures, family history of prostate cancer, personal habits, and medical care utilization, and demographic factors. Conditional logistic regression analyses showed that the odds ratio for prostate cancer associated with vasectomy was 0.86 (95% confidence interval 0.57-1.32) after adjustment for confounders. The odds ratio estimate did not differ substantially by age at vasectomy or time since vasectomy. However, the odds ratio estimate for prostate cancer associated with vasectomy tended to be increased among men who had a father or brother with prostate cancer. Nevertheless, the increased risk may be related to detection bias or differential participation rates due to both vasectomy status and a family history of prostate cancer. These results suggest no overall association between vasectomy and prostate cancer.

Adult↗
PubMed1996

Family history and survival of young women with invasive breast carcinoma.

BACKGROUND: This study investigates whether a positive family history of breast carcinoma is associated with improved survival after invasive breast carcinoma among women ages 21 through 45. METHODS: Subjects were 733 nonadopted women born after 1944 who were diagnosed with primary invasive breast carcinoma between January 1983 and April 1990 while residing in the metropolitan Seattle area and who provided information on family history of breast carcinoma. Information on clinical characteristics and survival was obtained from a population-based cancer registry. Subjects were followed for survival through 1994. Cox proportional hazards models were used to estimate the relative risk (RR) of dying in relation to family history of breast carcinoma, adjusting for selected clinical characteristics, age and year of diagnosis, and prior mammograms. RESULTS: The risk of dying among women with a first-degree family history of breast carcinoma was half that of women with no family history of breast carcinoma (RR = 0.5%; 95% confidence interval [CI], 0.3-0.9). There was no evidence of a reduction in the risk of dying among women with only a second-degree family history of breast carcinoma (RR = 1; 95% CI, 0.6-1.4). These associations were adjusted for age and year of diagnosis, stage of disease, tumor size, bilaterality, and mammogram history. These findings were not further influenced by adjustment for initial treatment or the numbers and ages of relatives at risk for breast carcinoma. CONCLUSIONS: Compared with women with neither a first- nor second-degree family history of breast carcinoma, the authors found that women who had a first-degree family history experienced increased survival. This finding did not appear to be attributable to differences in screening or treatment. To the extent that this difference is attributable to underlying biologic mechanisms, new insights into the natural history and treatment of breast carcinoma could result. Future studies should investigate whether specific susceptibility genes are associated with differential survival from breast carcinoma.

Adult↗
PubMed1996

Constitutional factors and sun exposure in relation to nevi: a population-based cross-sectional study.

A survey of benign melanocytic nevi (moles), suspected precursors or markers for melanoma, was conducted in Washington State among 717 randomly selected 18- to 50-year-old white adults who participated in a telephone interview in 1990-1991. Participants were questioned about constitutional factors, time spent in the sun, and severe sunburns over three time periods and were asked to count the raised nevi on both their arms. Logistic regression was used to examine the risk for 2+ nevi compared with none. An odds ratio (OR) of 2.0 (95% confidence interval (CI) 1.3-3.1) was seen for current freckling. Skin color, tendency to burn, and inability to tan were important risk factors but were not independent of each other. Individuals with a history of severe sunburns had an increased risk of nevi: OR = 1.9 (95% CI 0.9-3.9) for 3+ severe sunburns compared with none in the last 5 years; OR = 2.0 (95% CI 1.2-3.1) for 4+ severe teenage sunburns; and OR = 3.1 (95% CI 1.7-5.3) for 4+ severe childhood sunburns. Furthermore, childhood sunburns were related to nevi independently of sun sensitivity and teenage and recent sunburns: OR = 2.0 (95% CI 1.0-4.0) for 4+ severe sunburns. These data suggest that childhood sunburns are important in the etiology of nevi. This study supports prior studies of the relation between melanoma and early sun exposure.

Adolescent↗
PubMed1996

Risk of endometrial cancer following cessation of menopausal hormone use (Washington, United States).

While there are a number of benefits to the health of postmenopausal women from use of unopposed estrogens, the increased risk of endometrial cancer related to these hormones has led many women to use combined estrogen-progestogen therapy instead, or not to use hormones at all. Most women who take hormones do so only in the early portion of their postmenopausal years, so the risk of endometrial cancer following cessation of use might bear heavily on the overall risk/benefit evaluation. We analyzed data from a case-control study of women in western Washington (United States) to assess the magnitude of excess risk of endometrial cancer following discontinuation of estrogen use. Cases (n = 661) consisted of women aged 45 to 74 diagnosed between 1985 and 1991 who resided in one of three countries in Washington State. Controls (n = 865) were identified by random-digit dialing. Subjects were interviewed in-person to ascertain current and prior hormone use. The analysis was restricted to women who had not received combined estrogen-progestin therapy. Among women who had used unopposed estrogens at some time, risk of endometrial cancer declined as time since last use increased. Nonetheless, even among women who used these hormones for just a few years, the risk remained elevated by 30 to 70 percent almost a decade after cessation. These results, combined with those of most (but not all) other studies of this issue, suggest that a women who has discontinued unopposed estrogen therapy may retain a small increased risk of endometrial cancer for a long period of time.

Aged↗
PubMed1996

Nevi and migration within the United States and Canada: a population-based cross-sectional study.

A survey to ascertain factors associated with benign melanocytic nevi or moles was conducted among randomly-selected White adults (aged 18 to 50 years) in Washington State (United States). Participants of the telephone interview in 1990-91 were questioned about lifetime places of residence and constitutional factors. Subjects counted raised nevi on their arms at the end of the survey. Logistic regression was used to examine the risk for two or more nevi compared with no nevi. Individuals who resided in warmer areas and lower latitudes than Washington State were at higher risk of having multiple nevi. This association held for residence at birth, during childhood, adolescence, and over lifetime: an odds ratio (OR) of 2.3 (95 percent confidence interval = 1.2-4.3) for lifetime average daily maximum temperature of > or = 64 degrees F compared with 58.9 degrees F, and similar ORs of 2.1 for adolescence and 1.8 for childhood. These associations remained significant after adjusting for potential confounding effects of constitutional factors and for childhood sunburns as a potential mechanism. Risk of multiple nevi was reduced for both early age at migration and longer duration of stay in Washington. These data are consistent with the importance of childhood and adolescent sun exposure in the etiology of nevi, but also suggest an effect of lifetime sun exposure.

Adolescent↗
PubMed1996

A population-based study of contralateral breast cancer following a first primary breast cancer (Washington, United States)

To evaluate predictors of contralateral breast cancer risk, we examined data from a nested case-control study of second primary cancers among a cohort of women in western Washington (United States) diagnosed with breast cancer during 1978 through 1990 and identified through a population-based cancer registry. Cases included all women in the cohort who subsequently developed contralateral breast cancer at least six months after the initial diagnosis, but prior to 1992 (n = 234). Controls were sampled randomly from the cohort, matched to cases on age, stage, and year of initial breast cancer diagnosis. Information on potential risk factors for second primary cancer was obtained through medical record abstractions and physician questionnaires. Women who were postmenopausal due to a bilateral oophorectomy (i.e., a surgical menopause) at initial breast cancer diagnosis had a reduction in contralateral breast cancer risk compared with premenopausal women (matched odds ratio [mOR] = 0.25, 95 percent confidence interval [CI] = 0.09-0.68), whereas no reduction in risk was noted among postmenopausal women who had had a natural menopause (mOR = 0.90, CI = 0.39-2.09). Among postmenopausal women, there was a suggestion of a lower risk associated with relatively high parity (2+). A family history of breast cancer was associated with an increased risk (mOR = 1.96, CI = 1.22-5.15) and varied little by menopausal status. Having an initial tumor with a lobular component (c.f. a ductal histology) was not related strongly to risk (mOR = 1.47, CI = 0.79-2.74). The results of the present and earlier studies argue that we have limited ability to predict the occurrence of a contralateral breast tumor. Better predictors will be required before diagnostic and preventive interventions can be targeted to subgroups of patients with unilateral breast cancer.

Adult↗
PubMed1996

The relationship of human papillomavirus-related cervical tumors to cigarette smoking, oral contraceptive use, and prior herpes simplex virus type 2 infection.

It has now been established that infection with human papillomavirus (HPV) is necessary for the development of most cervical cancers. HPV is not sufficient for the development of cancer. Other exposures or host factors are necessary for cancer to occur. As part of an ongoing, population-based case-control study of invasive cervical cancer, we investigated the role of cigarette smoking, oral contraceptive (OC) use, and herpes simplex virus type 2 (HSV-2) as potential cofactors with HPV in the development of cervical cancer. Residents of three counties in western Washington State who were diagnosed with invasive squamous cell cervical cancer (n = 314) from January 1986 through December 1992 were interviewed about their sexual, reproductive, contraceptive, and cigarette smoking histories. Similar information was obtained from control women identified through random digit dialing (n = 672). The sera from 206 cases and 522 controls were tested for both HPV 16 capsid antibodies and HSV-2 antibodies. PCR was used to test paraffin-embedded tumor tissues for the presence of HPV DNA types 6, 16, 18, 31, 33, 35, and 39. Women with cervical cancer were more likely to be current smokers at diagnosis than population controls [relative risk (RR), 2.5; 95% confidence interval (CI), 1.8-3.4]. The risk associated with smoking was present to a similar extent among women positive and negative for HPV as measured by HPV 16 capsid antibodies and HPV DNA in the tumor tissue (cases). OC use was only important if first use was at an early age, particularly ages < or = 17 years (RR, 2.3; 95% CI, 1.4-3.8). There was only a slight risk for cervical cancer associated with antibodies to HSV-2 (RR, 1.2; 95% CI, 0.9-1.7). However, when we stratified by markers of HPV exposure, we found a significant increase in risk associated with HSV-2 among women negative for HPV 16 antibodies (RR, 2.0; 95% CI, 1.3-3.0), which was strengthened when we confined our analysis to cases whose tumors were HPV DNA negative (RR, 3.6; 95% CI, 1.6-8.0). There was no indication that cigarette smoking, OC use, or HSV-2 infection influence the ability of HPV infection to cause invasive cervical cancer. OC use may only be important in the etiology of invasive squamous cell cervical tumors if the use occurs at a critical time in the development of a woman's reproductive tract, at ages < or = 17 years. The majority of risk associated with HSV-2 was confined to HPV-negative tumors, indicating a possible separate pathway to disease that may account for 5-10% of invasive cervical cancers.

Adolescent↗
PubMed1996

Associations between human leukocyte antigen type and nasopharyngeal carcinoma in Caucasians in the United States.

A genetic component to nasopharyngeal carcinoma (NPC) has been suggested by associations of the malignancy with human leukocyte antigens (HLAs) in Southern Chinese populations, among which NPC is a major cancer. Data from other races are inconclusive. We have investigated associations between NPC and HLA antigens at the HLA-A, B, C, and DQ loci and alleles at the DRB1 locus in a population-based, multicenter investigation in the United States. Data from 82 cases and 140 controls are presented, making this the largest study population analyzing data from Caucasians to date. HLA frequencies from study cases were also compared with external control groups from the 11th International Histocompatibility Workshop and the National Marrow Donor Program. Logistic regression methods were used to investigate the effects of the joint occurrence of multiple HLA types and to assay for differences in HLA-associated risk in different age groups. A meta-analysis was undertaken to compare and summarize our results with previously published findings. The meta-analysis found a protective association with A2 antigen in non-Chinese [odds ratio (OR), 0.63; P < 0.001], a protective association with A11 across all races (OR, 0.54; P < 0.001), and an increased risk associated with B5 in Caucasians (OR, 2.81; P < 0.001). The present study also found independent associations, in a logistic regression model, between NPC and DRB1*1501 (OR, 0.33), DRB1*0405 (OR, 7.57), and Cw3 (OR, 0.42), although these data must be interpreted cautiously due to multiple-testing considerations. Associations were found to be more pronounced in younger patients for A2, A11, A28, B8, and B51.

Adult↗