Gender-Based Comorbidity in Benign Paroxysmal Positional Vertigo

It has been noted that benign paroxysmal positional vertigo (BPPV) may be associated with certain disorders and medical procedures. However, most studies to date were done in Europe, and epidemiological data on the United States (US) population are scarce. Gender-based information is even rarer. Furthermore, it is difficult to assess the relative prevalence of each type of association based solely on literature data, because different comorbidities were reported by various groups from different countries using different patient populations and possibly different inclusion/exclusion criteria. In this study, we surveyed and analyzed a large adult BPPV population (n = 1,360 surveyed, 227 completed, most of which were recurrent BPPV cases) from Omaha, NE, US, and its vicinity, all diagnosed at Boys Town National Research Hospital (BTNRH) over the past decade using established and consistent diagnostic criteria. In addition, we performed a retrospective analysis of patients’ diagnostic records (n = 1,377, with 1,360 adults and 17 children). The following comorbidities were found to be significantly more prevalent in the BPPV population when compared to the age- and gender-matched general population: ear/hearing problems, head injury, thyroid problems, allergies, high cholesterol, headaches, and numbness/paralysis. There were gender differences in the comorbidities. In addition, familial predisposition was fairly common among the participants. Thus, the data confirm some previously reported comorbidities, identify new ones (hearing loss, thyroid problems, high cholesterol, and numbness/paralysis), and suggest possible predisposing and triggering factors and events for BPPV.     

Serum Estradiol Correlates With Benign Paroxysmal Positional Vertigo in Postmenopausal Women

BackgroundA high incidence of benign paroxysmal positional vertigo (BPPV) is reported in postmenopausal women, and the association between estradiol (E2) deficiency and the occurrence of BPPV was investigated.MethodsPostmenopausal women with and without BPPV were included from 2016 to 2019, and 1-year follow-up was performed. Serum otolin-1 and E2 levels were assayed before the canalith repositioning treatment. Bone mineral density (BMD) was measured with a dual-energy x-ray absorptiometry scan. Receiver operating characteristic analysis was performed to determine the occurrence of BPPV, and Pearson analysis was performed to indicate the correlation between E2, otolin-1, and BMD.ResultsEighty-six postmenopausal women with BPPV and 80 age-, demographics-, and clinical characteristics-matched normal postmenopausal women were enrolled. Decreased E2 levels, increased otolin-1 levels, and decreased BMD were observed in postmenopausal women with BPPV, and increased BMD and decreased otolin-1 levels were observed in patients with higher levels of serum E2. Receiver operating characteristic analysis revealed that E2, otolin-1, and BMD showed low sensitivity and moderate specificity to determine the occurrence of BPPV. On the other hand, a low correlation coefficient was found between E2 and otolin-1, or BMD. It is worth noting that low E2 levels were found in the relapsed patients with BPPV after a 1-year follow-up.ConclusionE2 deficiency is correlated with the occurrence of BPPV, which may be a potential risk biomarker for postmenopausal women.     

Impact of Postmaneuver Sleep Position on Recurrence of Benign Paroxysmal Positional Vertigo

Background

The necessity of postural restriction to patients suffering from benign paroxysmal positional vertigo is controversial.

Objective

To investigate the impact of the sleep position after the repositioning maneuver on BPPV recurrence.

Methods

150 unilateral BPPV patients who were treated by repositioning maneuver were distributed into two groups. The patients in group A were instructed to sleep in a semi-sitting position at an angle of approximately 30 degrees and refrain from sleeping on their BPPV affected side for one week. The patients in group B were told to sleep in any preferred position. The comparison of recurrence rates according to different actual sleep positions in one week and one month was performed.

Results

There was a statistically significant correlation between the sleeping side and the side affected by BPPV. Without instructions on postural restriction, most patients (82.9%, 73/88) avoided sleeping on their affected side. The patients sleeping on their affected side had a higher recurrence rate (35.3%) than ones sleeping in other positions in the first week after the repositioning maneuver (p<0.05, Chi-square test and Fisher''s exact test). The patients sleeping randomly in following 3 weeks had a lower recurrence rate than ones sleeping in other position (p<0.05, Fisher''s exact test).

Conclusions

BPPV patients had a poor compliance to postural instructions. The habitual sleep side was associated with the side affected by BPPV. The patients sleeping on their affected side had a higher recurrence rate than those sleeping in other positions in first week after the repositioning maneuver.     

Association between Schizophrenia and Urinary Calculi: A Population-Based Case-Control Study

Background

People with schizophrenia have been demonstrated to have higher overall morbidity and all-cause mortality rates from general medical conditions. However, little attention has been given to the urinary system of people with schizophrenia. As no direct evidence has been reported demonstrating a link between schizophrenia and urinary calculi, this study utilized a population-based case-control study design to investigate the possibility of an association between schizophrenia and the occurrence of urinary calculi.

Method

This study used data from the Taiwan Longitudinal Health Insurance Database. Cases consisted of 53,965 urinary calculi patients newly diagnosed between 2002 and 2008. In total, 269,825 controls were randomly selected and matched with the cases in terms of age and sex. Each person was traced to discern whether he had previously received a diagnosis of schizophrenia. Conditional logistic regression models were performed for the analysis.

Results

A total of 3,119 (1.0%) subjects had been diagnosed with schizophrenia prior to the index date. This included 0.7% of the patients with urinary calculi, and 1.0% of the controls. A prior diagnosis of schizophrenia was independently associated with a 30% decrease (95% CI = 0.62–0.76) in the occurrence of urinary calculi. The reduction was even more remarkable in males (38%, 95% CI = 0.55–0.71) and in elder individuals independent of gender (48% in those aged >69, 95% CI = 0.36–0.77).

Conclusion

Our findings suggest that there is an inverse association between schizophrenia and urinary calculi. Future studies are needed to elucidate the mechanisms by which schizophrenia negatively associates with urinary calculi.     

Hospital Recorded Morbidity and Breast Cancer Incidence: A Nationwide Population-Based Case-Control Study

Introduction

Chronic diseases and their complications may increase breast cancer risk through known or still unknown mechanisms, or by shared causes. The association between morbidities and breast cancer risk has not been studied in depth.

Methods

Data on all Danish women aged 45 to 85 years, diagnosed with breast cancer between 1994 and 2008 and data on preceding morbidities were retrieved from nationwide medical registries. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using conditional logistic regression associating the Charlson comorbidity score (measured using both the original and an updated Charlson Comorbidity Index (CCI)) with incident breast cancer. Furthermore, we estimated associations between 202 morbidity categories and incident breast cancer, adjusting for multiple comparisons using empirical Bayes (EB) methods.

Results

The study included 46,324 cases and 463,240 population controls. Increasing CCI score, up to a score of six, was associated with slightly increased breast cancer risk. Among the Charlson diseases, preceding moderate to severe renal disease (OR = 1.25, 95% CI: 1.06, 1.48), any tumor (OR = 1.17, 95% CI: 1.10, 1.25), moderate to severe liver disease (OR = 1.86, 95% CI: 1.32, 2.62), and metastatic solid tumors (OR = 1.49, 95% CI: 1.17, 1.89), were most strongly associated with subsequent breast cancer. Preceding myocardial infarction (OR = 0.89, 95% CI: 0.81, 0.99), connective tissue disease (OR = 0.87, 95% CI: 0.80, 0.94), and ulcer disease (OR = 0.91, 95% CI: 0.83, 0.99) were most strongly inversely associated with subsequent breast cancer. A history of breast disorders was associated with breast cancer after EB adjustment. Anemias were inversely associated with breast cancer, but the association was near null after EB adjustment.

Conclusions

There was no substantial association between morbidity measured with the CCI and breast cancer risk.     

Medical Risk Factors Associated with Cholangiocarcinoma in Taiwan: A Population-Based Case-Control Study

Background

Cholangiocarcinoma, including intra- and extrahepatic cholangiocarcinoma, is a rare but highly lethal cancer. Despite effort in finding the risk factors of cholangiocarcinoma, the causes of most cholangiocarcinoma remain unknown. This study utilized a population-based case-control design using data from the National Health Insurance Research Database (NHIRD) of Taiwan to assess the medical conditions associated with cholangiocarcinoma.

Methods

5,157 incident cases of cholangiocarcinoma diagnosed during 2004 to 2008 and 20,628 controls matched to the cases on sex, age, and time of diagnosis (reference date for the controls) were identified from the NHIRD. Medical risk factors were ascertained from the NHIRD for each individual. Conditional logistic regression was performed to evaluate the association between cholangiocarcinoma and each medical risk factor.

Results

The results showed that factors associated with an increased risk of cholangiocarcinoma included cholangitis, cholelithiasis, cholecystitis, cirrhosis of liver, alcoholic liver disease, chronic non-alcoholic liver disease, hepatitis B, hepatitis C, diabetes, chronic pancreatitis, inflammatory bowel disease, and peptic ulcer. In addition, sex and age differences were observed.

Conclusions

This study confirms the association between cholangiocarcinoma and several less established risk factors, including diabetes, inflammatory bowel disease, hepatitis B, hepatitis C, and peptic ulcer (proxy for the presence of Helicobacter Pylori). Future studies should focus on finding additional environmental and genetic causes of cholangiocarcinoma.     

Herpes Zoster Is Associated with Prior Statin Use: A Population-Based Case-Control Study

Background

This study investigated the association between statin use and herpes zoster (HZ) occurrence in a population-based case-control study.

Methods

Study subjects were retrieved from the Taiwan Longitudinal Health Insurance Database 2000. This study included 47,359 cases with HZ and 142,077 controls. We performed conditional logistic regression analyses to calculate the odds ratio (OR) to present the association between HZ and having previously been prescribed statin.

Results

We found that 13.0% of the sampled subjects had used statins, at 15.5% and 12.1% for cases and controls, respectively (p<0.001). A conditional logistic regression analysis suggested that the adjusted OR of being a statin user before the index date for cases was 1.28 (95% confidence interval (CI): 1.24∼1.32) compared to controls. Subjects aged 18∼44 years had the highest adjusted OR for prior statin use among cases compared to controls (OR: 1.69; 95% CI: 1.45∼1.92). Furthermore, we found that the ORs of being a regular and irregular statin user before the index date for cases were 1.32 (95% CI: 1.27∼1.38) and 1.23 (95% CI: 1.181.29), respectively, compared to controls.

Conclusions

We concluded that prior statin use was associated with HZ occurrence.     

Familial Correlations of Onset Age of Hepatocellular Carcinoma: A Population-Based Case-Control Family Study

Background

There was lack of evidence for familial aggregation in onset age of hepatocellular carcinoma (HCC) in Chinese population. We conducted a population-based case-control family study to examine familial correlation of age of HCC onset in Taixing, China.

Methods

A total of 202 cases and 202 matched controls as well as their relatives were included in the study. Lifetime cumulative risks of HCC were estimated using the Kaplan-Meier approach. Cross ratios (CRs) were obtained from stratified Cox proportional hazard models, to assess the familial correlation of onset age.

Results

The mean age of HCC onset was decreased as increasing number of HCC cases in a family. The onset age was the earliest for first-degree relatives, intermediate for second-degree relatives, and latest for non-blood relatives (spouse) (log-rank test, P<0.01). The onset age was significantly correlated between probands and their relatives. In stratified Cox proportional hazard models, the CRs for the probands versus their fathers, mothers, siblings and uncles/aunts were 6.25 (95% confidence interval (CI): 1.84–21.25), 9.81 (95% CI: 1.24–77.56), 6.22 (95% CI: 1.37–28.36) and 3.24 (95% CI: 1.26–8.33), respectively. After adjustment for hepatitis B virus infection, the CRs remained significant.

Conclusion

This current study suggested a significant correlation of onset age for HCC among blood relatives. Familial HCC cases yielded earlier age of onset and their relatives have higher HCC risk in early age, highlighting intensive surveillance should be start at an earlier age for individuals with family history of HCC.     

Increased Risk of Acute Angle Closure in Retinitis Pigmentosa: A Population-Based Case-Control Study

Purpose

To investigate the association between retinitis pigmentosa (RP) and acute angle closure during a 15-year follow-up period.

Methods

Using the Taiwan Longitudinal Health Insurance Database 2000, we identified 382 RP patients based on the diagnostic code of RP (International Classification of Diseases, 9^th Revision, Clinical Modification (ICD-9-CM) 362.74) made during 1996–2010, excluding subjects under age of 20 years at diagnosis or subjects undergoing lens extraction before the index date. The control group included 3820 randomly selected non-RP subjects matched with the RP patients in age, gender and the index date of diagnosis. The incidence of acute angle closure during the study period was observed based on an ICD-9-CM code of 365.22. Cochran-Mantel-Haenszel test was used to determine the odds ratio (OR) of having acute angle closure in RP patients.

Results

The mean age at the diagnosis of RP was 51.1years (standard deviation [SD] 16.7). Acute angle closure occurred in 5 RP patients (1.3%) and in 15 controls (0.4%). The mean age with the acute angle closure was 53.3 years (SD 8.0) in RP patients and 64.6 years (SD 8.4) in controls (P = 0.015). After adjusting for age, gender and comorbid disorders, RP patients had 3.64-fold (95% confidence interval [CI], 1.29–10.25, P<0.001) greater odds of having acute angle closure. After stratification for gender and age, the risk of acute angle closure in RP was higher in patients under age of 60 years (adjusted OR 11.84; 95% CI, 2.84–49.48) and male patients (adjusted OR 19.36; 95% CI, 3.43–109.40)(both P = 0.001).

Conclusions

RP patients had increased risk of acute angle closure than controls. Contrary to the fact that angle closure disease is more prevalent in elderly females in general population, acute angle closure attack occurred earlier in life and the risk was higher in males among RP patients.     

Association between Neovascular Age-Related Macular Degeneration and Dementia: A Population-Based Case-Control Study in Taiwan

Background

Most available studies focusing on the association between neovascular age-related macular degeneration (AMD) and dementia have conflicting results. This study aimed to investigate the association between previously diagnosed AMD and dementia using a population-based dataset in Taiwan.

Methods

Data for this case-control study were retrospectively collected from the Taiwan National Health Insurance Research Database. We identified 13,402 subjects who had a diagnosis of dementia as cases, and 40,206 subjects without dementia as controls. A conditional logistic regression was used to examine the association of dementia with previously diagnosed neovascular AMD.

Results

We found that of the study sample of 53,608 subjects, 1.01% had previously diagnosed neovascular AMD, 1.35% and 0.90% for cases and the controls, respectively (p<0.001). The conditional logistic regression analysis suggested that the odds ratio of prior neovascular AMD for cases was 1.37 (95% confidence interval: 1.14~1.65) compared to the controls after adjusting for subjects’ age, monthly income, geographic location, urbanization level, and hyperlipidemia, diabetes, hypertension, stroke, ischemic heart disease, and whether or not a subjects underwent cataract surgery prior to index date than controls.

Conclusions

Dementia subjects were associated with a higher proportion of prior neovascular AMD than were the controls.     

Family Characteristics as Risk Factors for Childhood Acute Lymphoblastic Leukemia: A Population-Based Case-Control Study

Background

To date, few risk factors for childhood acute lymphoblastic leukemia (ALL) have been confirmed and the scientific literature is full of controversial “evidence.” We examined if family characteristics, particularly maternal and paternal age and number of older siblings, were risk factors for childhood acute lymphoblastic leukemia (ALL).

Methodology/Principal Findings

In this population-based nationwide matched case-control study, patients 0–14 years of age with ALL diagnosed 1991–2006 and registered in the Swiss Childhood Cancer Registry were linked with their census records of 1990 and 2000. Eight controls per case were selected from the census. The association between family characteristics and ALL was analyzed by conditional logistic regressions. We found that increasing maternal age was associated with incidence of ALL in the offspring (OR per 5-year increase in maternal age 1.18, 95% CI 1.05–1.31; p = 0.004), remaining stable (trend OR 1.14, 95% CI 0.99–1.31; p = 0.060) after adjustment for other risk factors. The association with paternal age was weaker (OR per 5-year increase 1.14, 95% CI 1.01–1.28, p = 0.032) and disappeared after adjustments. Number of older siblings was not associated with risk of ALL in the overall group of children aged 0–14 years at diagnosis. However, we found a negative trend between number of older siblings and ALL diagnosed at age 0–4 years (OR per sibling 0.85, 95% CI 0.68–1.06; p = 0.141) and a positive trend for ALL diagnosed at age 5–9 (OR 1.34, 95% CI 1.05–1.72; p = 0.019), with some evidence for an effect modification (p-value for interaction  = 0.040).

Conclusions

As in other studies, increasing maternal, but not paternal age was associated with risk of ALL. We found only a weak association with the number of older siblings, suggesting a delay in disease manifestation rather than a decrease in incidence.     

Impact of Bisphosphonate-related Osteonecrosis of the Jaw on Osteoporotic Patients after Dental Extraction: A Population-Based Cohort Study

Background and Aims

Little is currently known about the risk of developing bisphosphonate-related osteonecrosis of the jaw (BRONJ). This study sought to determine the incidence of BRONJ in osteoporotic patients. We also sought to identify the nature and types of risk factors of osteonecrosis of jaw (ONJ) related to the use of oral bisphosphonates (BPs).

Materials and Methods

Data from the National Health Insurance system of Taiwan. This cohort study included 19,399 adult osteoporosis patients received dental extraction in 2000-2010 (osteoporosis cohort) and 38,669 age and gender matched comparisons selected from dental extraction people without osteoporosis and osteonecrosis history (comparison cohort). All study subjects were followed from the date of their dental extraction (index date) to the development of ONJ and were included in the study up to 2011 or were lost to the study, whichever occurred first. Cox proportional hazard regression was used to estimate the hazard ratio and 95% confidence intervals for the two cohorts.

Results

Patients with osteoporosis had a significantly higher risk to develop ONJ than healthy persons (adjusted HR, 2.05; 95% confidence interval, 1.58–2.65). The risk of ONJ increased with the severity of osteoporosis, no matter whether patient with cancer or not. A cumulative effect of dental extraction frequency may increase the risk of ONJ.

Conclusions

We concluded that ONJ is caused by a number of factors. Osteoporosis and past dental history play the very important roles, while BPs play the synergistic effect.     

Risk of Rheumatoid Arthritis in Patients with Type 2 Diabetes: A Nationwide Population-Based Case-Control Study

Objective

Type 2 diabetes is associated with chronic, low-grade inflammation and could potentially trigger the progression of other, more prominent inflammatory diseases such as rheumatoid arthritis (RA). Therefore, we aimed to investigate the risk of incident RA in Taiwanese patients with type 2 diabetes using a population-based health claims database.

Methods

This nationwide, population-based, case-control study used administrative data to identify 1,416 patients with RA (age ≥20 years) as cases and 7,080 controls that were frequency-matched for sex, 10-year age group, and year of catastrophic illness certificate application date (index year). All subjects were retrospectively traced back, up to 13 years prior to the index year, for their first diagnosis of type 2 diabetes. Logistic regression analysis was conducted to quantify the association between incident RA and type 2 diabetes.

Results

The odds of developing RA were significantly higher in female (odds ratio [OR] 1.46, 95% confidence interval [95% CI] 1.24–1.72) but not in male (OR 1.00, 95% CI 0.72–1.37) patients who had previously diagnosed with type 2 diabetes. Subgroup analysis indicated that the odds of developing RA were more prominent in younger females (20 to 44 years of age) with type 2 diabetes. In addition, the odds of developing RA in female patients with type 2 diabetes were higher in those with a shorter time interval between the diagnosis of type 2 diabetes and RA.

Conclusions

This large nationwide, population-based, case-control study showed an elevated risk of RA in female Taiwanese patients with type 2 diabetes. Our findings were consistent with the hypothesis that chronic low-grade inflammation in type 2 diabetes may elicit the development of RA in genetically susceptible individuals.     

High Intake of Energy and Fat in Southwest Chinese Women with PCOS: A Population-Based Case-Control Study

BackgroundPolycystic ovary syndrome (PCOS) is a common reproductive endocrinological disease with heterogeneous phenotype. Obesity contributes to the increased prevalence and severity of PCOS. Whether the intakes of major nutrients are higher in Chinese PCOS patients is still unknown.ObjectivesTo study the intakes of total energy, protein, fat and carbohydrate in Southwest Chinese PCOS patients.Methods1854 women were included in the cross-sectional study. A population-based case-control study was conducted. The dietary habits and nutrients intake status of 169 PCOS patients and 338 age-matched controls were investigated by the method of semi-quantitative food frequency questionnaire.ResultsThe actual intake of total energy (P = 0.01) and fat (P = 0.01) were higher, but carbohydrate was lower (P = 0.01) in PCOS patients as compared with the controls. The energy percentage supplied by protein (12.33%±2.27% vs. 19.26%±5.91%, P<0.001) and carbohydrate (48.72%±6.41% vs. 68.31%±8.37%, P<0.001) were lower in Southwest Chinese PCOS patients than those of control, however, the energy percentage supplied by fat was higher (38.95%±5.71% vs. 12.42%±5.13%, P<0.001) in PCOS.ConclusionsLimit the intake of total energy and fat shall be recommended to the Southwest Chinese PCOS patients. Women with PCOS in Southwest China shall consult with the nutritionist for improving the dietary structure.     

Maternal Age,Parity and Isolated Birth Defects: A Population-Based Case-Control Study in Shenzhen,China

Background

The etiology of birth defects has been widely studied but is not yet fully clarified, previously published data had suggested that maternal age or parity maybe involved, but without consistent conclusions.

Methods

A population-based, case-control study was nested in a cohort of perinatal infants born from 2010 to 2012 in Baoan District, Shenzhen. Four categories of isolated birth defects were defined as cases: congenital heart defects (CHD, n = 693), polydactyly (n = 352), cleft lip with or without palate (CL/P, n = 159) and equinovarus (n = 119). Controls were non-malformed infants (n = 11,307) randomly selected from the same area and period. Odds ratios (ORs) and the 95% confidence intervals (CIs) were computed by multivariable unconditional logistic regression analysis.

Results

Young maternal age (<25 years old) was associated with a reduced risk of CHD (adjusted OR = 0.73, 95% CI 0.59–0.90), while with an elevated risk of polydactyly (adjusted OR = 1.42, 95% CI 1.09-1.84). Increased risk of CL/P-affected pregnancy was observed in mothers older than 35 years old (adjusted OR = 2.12, 95% CI 1.26–3.57). Compared to primipara, those having their second, and third or more delivery were less likely to have infants with equinovarus, with significant adjusted ORs of 0.59 (0.40–0.89) and 0.42 (0.19–0.93), respectively.

Conclusion

Maternal age was significantly associated with CHD, polydactyly and CL/P relevant pregnancy. Mothers with higher parity might have lower risk of equinovarus occurrence in offsprings.     

Previous Exposure to Statin May Reduce the Risk of Subsequent Non-Hodgkin Lymphoma: A Nationwide Population-Based Case-Control Study

Background

The purpose of this study was to investigate the association between previous exposure to statins and the risk of non-Hodgkin lymphoma (NHL).

Methods

This nationwide population-based case–control study was conducted using the National Health Insurance Research Database of Taiwan. The NHL group consisted of the patients with a first-time diagnosis of NHL between 2005 and 2008. The cases of the control group were pair-matched to the NHL group according to sex, year of birth and date of NHL diagnosis (index date). The statin administration data from both groups were retrospectively collected from the index date to January 1, 1996. The cumulative defined daily dose (cDDD) was estimated to evaluate the statin exposure. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariate logistic regression.

Results

The study population was composed of 1715 NHL patients and 16942 control subjects. The analysis revealed that previous statin administration was associated with a reduced risk of subsequent NHL with an adjusted OR of 0.52 (95% CI, 0.43–0.62). Additionally, there was a dose-response relationship between statin administration and the risk of NHL. The adjusted ORs were 0.63 (95% CI, 0.46–0.86), 0.58 (95% CI, 0.42–0.79), 0.51 (95% CI, 0.38–0.67), and 0.36 (95% CI, 0.24–0.53) for the subjects with statin administrations of fewer than 28, 28 to 90, 91 to 365, and more than 365 cDDDs, respectively, relative to the subjects without any statin administration.

Conclusions

The results of this study suggest that previous statin administration is associated with a lower risk of subsequent NHL. As statins are widely used medications, the magnitude of the risk reduction may have a substantial influence on public health. Further studies to confirm our findings are warranted.     

Social Participation and Dental Health Status among Older Japanese Adults: A Population-Based Cross-Sectional Study

Background

Although social participation is a key determinant of health among older adults, few studies have focused on the association between social participation and dental health. This study examined the associations between social participation and dental health status in community-dwelling older Japanese adults.

Methods and Findings

In 2010, self-administered postal questionnaires were distributed to all people aged ≥65 years in Iwanuma City, Japan (response rate, 59.0%). Data from 3,517 respondents were analyzed. Data on the number of remaining natural teeth, for determining the dental health status, and social participation were obtained using self-administered questionnaires. The number, type, and frequency of social activities were used to assess social participation. Social activities were political organizations or associations, industrial or professional groups, volunteer groups, senior citizens'' clubs, religious groups or associations, sports groups, neighborhood community associations, and hobby clubs. Using ordinal logistic regression, we calculated the odds ratios (OR) and 95% confidence intervals (95% CI) for an increase in category of remaining teeth based on the number, type, and frequency of social activities. Sex, age, marital status, current medical history, activity of daily living, educational attainment, and annual equivalent income were used as covariates. Of the respondents, 34.2% reported having ≥20 teeth; 27.1%, 10–19 teeth; 26.3%, 1–9 teeth; and 12.4%, edentulousness. Social participation appeared to be related with an increased likelihood of having a greater number of teeth in old age, even after adjusting for covariates (OR = 1.30, 95% CI = 1.10–1.53). Participation in sports groups, neighborhood community associations, or hobby clubs was significantly associated with having more teeth.

Conclusions

Our results suggest a protective effect of social participation on dental health. In particular, participation in sports groups, neighborhood community associations, or hobby clubs might be a strong predictor for retaining more teeth in later life.     

Fathering of Dizygotic Twins and Risk of Prostate Cancer: Nationwide,Population-Based Case-Control Study

Background

An association between male fertility and risk of prostate cancer has been suggested, possibly through lower androgen levels in subfertile men. We evaluated male fertility in relation to risk of prostate cancer by assessing the frequency of fathering of dizygotic twins, a marker of high fertility, among cases of prostate cancer and controls.

Methods

We performed a case-control study in Prostate Cancer data Base Sweden (PCBaSe), a nationwide, population-based cohort. PCBaSe was linked to the Swedish twin register for information on zygosity for same-sex twins and to other nationwide health care registers and demographic databases for information on socioeconomic factors, comorbidity, and tumor characteristics for 96 301 prostate cancer cases and 378 583 matched controls. To account for the influence of in vitro fertilization on dizygotic twinning, analyses were restricted to men who had fathered children before 1991, when in vitro fertilization was still uncommon in Sweden.

Results

1 112 cases and 4 538 controls had fathered dizygotic twins. Men with dizygotic twins had no increased risk of prostate cancer compared to fathers of singletons; neither for total prostate cancer odds ratio (OR) 0.95(95% CI 0.89–1.02), nor for any risk category, OR 0.97 (95% CI 0.84–1.12) for low-risk disease, and OR 1.04 (95% CI 0.90–1.22) for metastatic disease.

Conclusion

The lack of association between fathering of dizygotic twins and prostate cancer risk give no support for an association between male fertility and prostate cancer risk.     

Psychiatric Disorders after Epilepsy Diagnosis: A Population-Based Retrospective Cohort Study

Background

Psychiatric manifestations after occurrence of epilepsy have often been noted. However, the association between newly diagnosed epilepsy and psychiatric disorders afterward is not completely understood. We conducted two longitudinal cohorts for patients with and without epilepsy to investigate the risk factors and hazard ratios of developing psychiatric disorders after patients were newly diagnosed with epilepsy.

Methods

We identified 938 patients with a new diagnosis of epilepsy and 518,748 participants without epilepsy from the National Health Insurance Research Database in 2000–2002 and tracked them until 2008. We compared the incidence of developing psychiatric disorders between the two cohorts, evaluated risk factors and measured the associated hazard ratios (HRs) and 95% confidence intervals (CIs) of developing psychiatric disorders.

Findings

The incidences of psychiatric disorders for people with and without epilepsy were 94.1 and 22.6 per 1000 person-years, respectively. After adjusting the covariates, the epilepsy cohort showed the highest risks in mental retardation (HR 31.5, 95% CI 18.9 to 52.4), bipolar disorder (HR 23.5, 95% CI 11.4 to 48.3) and alcohol or drug psychosis (HR 18.8, 95% CI 11.1 to 31.8) among psychiatric complications developed after newly diagnosed epilepsy. The risk increased with epileptic general seizure and frequency of outpatient visits for epilepsy, as well as with emergency room visits and hospitalizations for epilepsy, and with older age. Chronologically, the highest risk occurred in the first year after epilepsy diagnosis (HR 11.4, 95% CI 9.88 to 13.2).

Conclusion

Various psychiatric disorders were demonstrated after newly diagnosed epilepsy and closely related to general seizure and use of medical services for epilepsy. This shows a need for integrated psychiatric care for patients newly diagnosed with epilepsy, especially in the first year.