Pooling controls from nested case-control studies with the proportional risks model.

The standard approach to regression modeling for cause-specific hazards with prospective competing risks data specifies separate models for each failure type. An alternative proposed by Lunn and McNeil (1995) assumes the cause-specific hazards are proportional across causes. This may be more efficient than the standard approach, and allows the comparison of covariate effects across causes. In this paper, we extend Lunn and McNeil (1995) to nested case-control studies, accommodating scenarios with additional matching and non-proportionality. We also consider the case where data for different causes are obtained from different studies conducted in the same cohort. It is demonstrated that while only modest gains in efficiency are possible in full cohort analyses, substantial gains may be attained in nested case-control analyses for failure types that are relatively rare. Extensive simulation studies are conducted and real data analyses are provided using the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) study.

Plasma metabolomics profiles and breast cancer risk.

BACKGROUND: Breast cancer (BC) is the most common cancer in women and incidence rates are increasing; metabolomics may be a promising approach for identifying the drivers of the increasing trends that cannot be explained by changes in known BC risk factors. METHODS: We conducted a nested case-control study (median followup 6.3 years) within the New York site of the Breast Cancer Family Registry (BCFR) (n = 40 cases and 70 age-matched controls). We conducted a metabolome-wide association study using untargeted metabolomics coupling hydrophilic interaction liquid chromatography (HILIC) and C18 chromatography with high-resolution mass spectrometry (LC-HRMS) to identify BC-related metabolic features. RESULTS: We found eight metabolic features associated with BC risk. For the four metabolites negatively associated with risk, the adjusted odds ratios (ORs) ranged from 0.31 (95% confidence interval (CI): 0.14, 0.66) (L-Histidine) to 0.65 (95% CI: 0.43, 0.98) (N-Acetylgalactosamine), and for the four metabolites positively associated with risk, ORs ranged from 1.61 (95% CI: 1.04, 2.51, (m/z: 101.5813, RT: 90.4, 1,3-dibutyl-1-nitrosourea, a potential carcinogen)) to 2.20 (95% CI: 1.15, 4.23) (11-cis-Eicosenic acid). These results were no longer statistically significant after adjusting for multiple comparisons. Adding the BC-related metabolic features to a model, including age, the Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm (BOADICEA) risk score improved the accuracy of BC prediction from an area under the curve (AUC) of 66% to 83%. CONCLUSIONS: If replicated in larger prospective cohorts, these findings offer promising new ways to identify exposures related to BC and improve BC risk prediction.

Subsequent primary neoplasms after childhood cancer therapy - design and description of the German nested case-control study STATT-SCAR.

BACKGROUND: Subsequent primary neoplasms (SPN) are among the most severe late effects and the second most frequent cause of death in childhood cancer patients. In this paper we introduce method and properties of the STATT-SCAR study (Second Tumor After Tumor Therapy, Second Cancer After Radiotherapy), which is a joint nested matched case-control study to evaluate the impact of chemotherapy (STATT) as well as radiotherapy (SCAR) on the risk of developing a SPN. METHODS: Based on the cohort of the German childhood cancer registry (GCCR), we selected patients diagnosed with a first neoplasm before age 15 or younger between 1980 and 2014. We selected those with a SPN at least half a year after the first neoplasm, and matched up to four controls to each case. Therapy data were acquired from various sources, including clinical study centers and treating hospitals. To analyze the impact of radiotherapy, organ doses were estimated by using reconstructed treatment plans. The effect of chemotherapy was analyzed using substance groups summarized after isotoxic dose conversion. RESULTS: 1244 cases with a SPN were identified and matched with 4976 controls. Treatment data were acquired for 83% of all match groups (one case and at least one control). Based on preliminary analyses, 98% of all patients received chemotherapy and 54% of all patients were treated with radiotherapy. CONCLUSIONS: Based on our data, detailed analyses of dose response relationships and treatment element combinations are possible, leading to a deeper insight into SPN risks after cancer treatments. TRIAL REGISTRATION: The study is registered at the German clinical trial register (DRKS) under number DRKS00017847 [45].

IVF and risk of Type 1 diabetes mellitus: a population-based nested case-control study.

STUDY QUESTION: Is the mode of conception (natural, subfertility and non-IVF, and IVF) associated with the risk of Type 1 diabetes mellitus among offspring? SUMMARY ANSWER: The risk of Type 1 diabetes in offspring does not differ among natural, subfertility and non-IVF, and IVF conceptions. WHAT IS KNOWN ALREADY: Evidence has shown that children born through IVF have an increased risk of impaired metabolic function. STUDY DESIGN, SIZE, DURATION: A population-based, nested case-control study was carried out, including 769 children with and 3110 children without Type 1 diabetes mellitus within the prospective cohort of 2 228 073 eligible parent-child triads between 1 January 2004 and 31 December 2017. PARTICIPANTS/MATERIALS, SETTING, METHODS: Using registry data from Taiwan, the mode of conception was divided into three categories: natural conception, subfertility, and non-IVF (indicating infertility diagnosis but no IVF-facilitated conception), and IVF conception. The diagnosis of Type 1 diabetes mellitus was determined according to the International Classification of Diseases, 9th or 10th Revision, Clinical Modification. Each case was matched to four controls randomly selected after matching for child age and sex, residential township, and calendar date of Type 1 diabetes mellitus occurrence. MAIN RESULTS AND THE ROLE OF CHANCE: Based on 14.3 million person-years of follow-up (median, 10 years), the incidence rates of Type 1 diabetes were 5.33, 5.61, and 4.74 per 100 000 person-years for natural, subfertility and non-IVF, and IVF conceptions, respectively. Compared with natural conception, no significant differences in the risk of Type 1 diabetes were observed for subfertility and non-IVF conception (adjusted odds ratio, 1.04 [95% CI, 0.85-1.27]) and IVF conception (adjusted odds ratio, 1.00 [95% CI, 0.50-2.03]). In addition, there were no significant differences in the risk of Type 1 diabetes according to infertility source (male/female/both) and embryo type (fresh/frozen). LIMITATIONS, REASONS FOR CAUTION: Although the population-level data from Taiwanese registries was used, a limited number of exposed cases was included. We showed risk of Type 1 diabetes was not associated with infertility source or embryo type; however, caution with interpretation is required owing to the limited number of exposed events after the stratification. The exclusion criterion regarding parents' history of diabetes mellitus was only applicable after 1997, and this might have caused residual confounding. WIDER IMPLICATIONS OF THE FINDINGS: It has been reported that children born to parents who conceived through IVF had worse metabolic profiles than those who conceived naturally. Considering the findings of the present and previous studies, poor metabolic profiles may not be sufficient to develop Type 1 diabetes mellitus during childhood. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by grants from Shin Kong Wu Ho-Su Memorial Hospital (No. 109GB006-1). The funders had no role in considering the study design or in the collection, analysis, interpretation of data, writing of the report, or decision to submit the article for publication. The authors have no competing interests to disclose. TRIAL REGISTRATION NUMBER: N/A.

Maternal overweight and obesity modify the association of serum fibroblast growth factor 21 levels with gestational diabetes mellitus: A nested case-control study.

AIMS: To examine the prospective association between fibroblast growth factor 21 (FGF21) and risk of gestational diabetes mellitus (GDM) and the modifying effect of overweight/obesity for this association. METHODS: Serum FGF21 levels were measured at 6-15 weeks of gestation among 332 GDM cases and 664 matched controls. Conditional logistic regression was used to evaluate its association with GDM risk. Interaction analyses on multiplicative and additive scales were conducted to investigate the modifying effect of overweight/obesity. RESULTS: Elevated FGF21 levels were associated with a higher risk of GDM in multivariable models, but the positive association was attenuated after further adjustment for pre-pregnancy body mass index (BMI). A significant multiplicative interaction was noted between FGF21 (both continuous and dichotomous) and pre-pregnancy BMI (p for interaction = 0.049 and 0.03), and the association was only significant in participants with pre-pregnancy BMI ≥24 kg/m2 . When participants were grouped based on pre-pregnancy BMI (≥24 and <24 kg/m2 ) and FGF21 levels (≥median and

A Negative Association between Plasma Phylloquinone and All-Cause Mortality in Chinese Adults with Hypertension: A Nested Case-Control Study.

BACKGROUND: Previous studies have revealed that vitamin K is essential for preventing various chronic diseases. Phylloquinone is the primary dietary and circulating form of vitamin K. However, data concerning the association between plasma phylloquinone and all-cause mortality are limited. OBJECTIVES: This study aimed to evaluate the association between plasma phylloquinone and risk of all-cause mortality and examine some potential confounders. METHODS: This study is a post hoc analysis of the RCT and a nested, case-control design was used. Enrolled participants had to have hypertension at baseline. Study initiation was 19 May, 2008, and the median follow-up was 4.5 y. A total of 604 mortality cases and 604 controls matched for age, sex, treatment group, and study site were included in this study. Odds ratios (OR) and 95% confidence intervals (CIs) of all-cause mortality were calculated using conditional or unconditional logistic regression, without or with adjusting for pertinent covariates, respectively. The concentration of phylloquinone was measured by liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS). RESULTS: The mean and median phylloquinone levels were 1.62 nmol/L and 0.89 nmol/L, respectively. There was a significant negative association between log-transformed plasma phylloquinone and all-cause mortality after controlling for potential confounders (per 1 unit increase-OR: 0.79; 95% CI: 0.66, 0.95). Furthermore, the association of plasma phylloquinone with risk of all-cause mortality differed by body mass index (BMI) (<25 kg/m2 compared with ≥25 kg/m2, P-interaction = 0.004). A significant trend of decreasing risk with increasing concentration of phylloquinone was observed in participants with higher BMI (per 1 unit increase-OR: 0.71; 95% CI: 0.56, 0.90; P = 0.004). No significant correlation was found between phylloquinone and risk of all-cause mortality in those with BMI <25 kg/m2. CONCLUSIONS: In Chinese patients with hypertension, there was a significant negative association between baseline plasma phylloquinone and all-cause mortality, especially among those with higher BMI.

Age-stratified risk of suicide in patients with schizophrenia.

OBJECTIVES: Schizophrenia is associated with an increased risk of suicide. Few studies have investigated the risk of suicide across different ages, likely due to limitations around sample size. METHODS: From the National Health Insurance Research Database in Taiwan, this study identified 195,787 patients with schizophrenia from January 1, 2000, to December 31, 2019. During the study period, 3848 patients died from suicide. We calculated the standardized mortality ratio (SMR) for suicide stratified by age. In this age-stratified, nested case-control study, risk set sampling was used to match each case with 4 living controls by age, sex, and the year of the first diagnosis with schizophrenia. Conditional logistic regression was used for estimating age-stratified risk profiles. RESULTS: The SMR was the highest in the <25 years age group (52.8) and inversely correlated with age. Unemployment was associated with an increased risk of suicide in the 25 to 34, 35 to 44, 45 to 54, and 55 to 64 years age groups. Depressive and sleep disorders before suicide were more common among suicide cases with schizophrenia than among controls across all age groups. Drug-induced and alcohol-induced mental disorders were significantly associated with suicide but were observed only in the age group younger than 54. Heart disease, pneumonia, and moderate or severe renal disease were risk factors for suicide in the age groups less than 65. CONCLUSIONS: The risk factors for suicide differ by age. This study's findings can be used to optimize health-care interventions for preventing suicide in patients with schizophrenia.

Weighted metrics are required when evaluating the performance of prediction models in nested case-control studies.

BACKGROUND: Nested case-control (NCC) designs are efficient for developing and validating prediction models that use expensive or difficult-to-obtain predictors, especially when the outcome is rare. Previous research has focused on how to develop prediction models in this sampling design, but little attention has been given to model validation in this context. We therefore aimed to systematically characterize the key elements for the correct evaluation of the performance of prediction models in NCC data. METHODS: We proposed how to correctly evaluate prediction models in NCC data, by adjusting performance metrics with sampling weights to account for the NCC sampling. We included in this study the C-index, threshold-based metrics, Observed-to-expected events ratio (O/E ratio), calibration slope, and decision curve analysis. We illustrated the proposed metrics with a validation of the Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm (BOADICEA version 5) in data from the population-based Rotterdam study. We compared the metrics obtained in the full cohort with those obtained in NCC datasets sampled from the Rotterdam study, with and without a matched design. RESULTS: Performance metrics without weight adjustment were biased: the unweighted C-index in NCC datasets was 0.61 (0.58-0.63) for the unmatched design, while the C-index in the full cohort and the weighted C-index in the NCC datasets were similar: 0.65 (0.62-0.69) and 0.65 (0.61-0.69), respectively. The unweighted O/E ratio was 18.38 (17.67-19.06) in the NCC datasets, while it was 1.69 (1.42-1.93) in the full cohort and its weighted version in the NCC datasets was 1.68 (1.53-1.84). Similarly, weighted adjustments of threshold-based metrics and net benefit for decision curves were unbiased estimates of the corresponding metrics in the full cohort, while the corresponding unweighted metrics were biased. In the matched design, the bias of the unweighted metrics was larger, but it could also be compensated by the weight adjustment. CONCLUSIONS: Nested case-control studies are an efficient solution for evaluating the performance of prediction models that use expensive or difficult-to-obtain biomarkers, especially when the outcome is rare, but the performance metrics need to be adjusted to the sampling procedure.

OMICs Signatures Linking Persistent Organic Pollutants to Cardiovascular Disease in the Swedish Mammography Cohort.

Cardiovascular disease (CVD) development may be linked to persistent organic pollutants (POPs), including organochlorine compounds (OCs) and perfluoroalkyl and polyfluoroalkyl substances (PFAS). To explore underlying mechanisms, we investigated metabolites, proteins, and genes linking POPs with CVD risk. We used data from a nested case-control study on myocardial infarction (MI) and stroke from the Swedish Mammography Cohort - Clinical (n = 657 subjects). OCs, PFAS, and multiomics (9511 liquid chromatography-mass spectrometry (LC-MS) metabolite features; 248 proteins; 8110 gene variants) were measured in baseline plasma. POP-related omics features were selected using random forest followed by Spearman correlation adjusted for confounders. From these, CVD-related omics features were selected using conditional logistic regression. Finally, 29 (for OCs) and 12 (for PFAS) unique features associated with POPs and CVD. One omics subpattern, driven by lipids and inflammatory proteins, associated with MI (OR = 2.03; 95% CI = 1.47; 2.79), OCs, age, and BMI, and correlated negatively with PFAS. Another subpattern, driven by carnitines, associated with stroke (OR = 1.55; 95% CI = 1.16; 2.09), OCs, and age, but not with PFAS. This may imply that OCs and PFAS associate with different omics patterns with opposite effects on CVD risk, but more research is needed to disentangle potential modifications by other factors.

Prospective findings from the Dongfeng-Tongji cohort: Exposure to various metals, the expression of microRNA-4286, and the incidence of acute coronary syndrome.

Mounting evidence suggests that metal/metalloid exposure is related to the adverse health effects. Our prior investigation revealed a positive relation between the plasma level of microRNA-4286 (miR-4286) and an increased risk of developing acute coronary syndrome (ACS). However, it is a lack of studies evaluating the connection between metal/metalloid exposure and miRNA expression on ACS. In the prospective Dongfeng-Tongji cohort, we performed a nested case-control study. A total of 480 ACS and 480 controls were carefully selected based on similar age, sex, and blood collection time. Using inductively coupled plasma mass spectrometry, we assessed the plasma concentrations of 24 different metals. Quantitative real-time polymerase chain reaction was used to analyze the plasma miR-4286. We examined the relations of plasma metals with miR-4286 levels, the incidence of ACS, and the potential interactions. Using the multivariate conditional logistic regression models, we observed that the adjusted odds ratios (95% confidence intervals [CI]) for incident ACS were 1.79 (1.03, 3.12; P-trend = 0.03), 0.60 (0.41, 0.87; P-trend = 0.008), and 0.66 (0.46, 0.93; P-trend = 0.02), when comparing the extreme tertiles of aluminum, rubidium, and selenium, respectively. There was a relation between the concentration of rubidium in plasma and a decrease in the level of plasma miR-4286 (percent difference [95% CI]: -13.36% [-22.74%, -2.83%]; P-trend = 0.01). Both multiplicative (P interaction = 0.009) and additive interactions (relative excess risk due to interaction [95% CI]: 0.82 [0.59, 1.06]) were noted in our observation regarding the relationship between plasma aluminum and miR-4286 in incident ACS. The findings indicated that plasma aluminum was positively while plasma rubidium and selenium were negatively linked to an increased risk of developing ACS. Plasma aluminum exposure and plasma miR-4286 expression might synergistically affect the incident ACS risk. Controlling aluminum exposure was important for ACS prevention, especially for individuals with high expression of plasma miR-4286.

Perfluoroalkyl substances exposure and the risk of breast cancer: A nested case-control study in Jinchang Cohort.

BACKGROUND: As persistent organic pollutants (POPs), perfluoroalkyl substances (PFAS) may potentially impact human health. Our study aimed to investigate the prospective association between PFAS exposure and the incidence risk of breast cancer in females. METHODS: By fully following the Jinchang Cohort after a decade, we conducted this nested case-control study with 135 incidence cases of breast cancer (BC) and 540 bias-paired controls. The PFAS levels were tested by baseline serum samples. Conditional logistic regression and a restricted cubic spline model were employed to investigate the BC incidence risks and the dose-response associated with single PFAS component exposure. Furthermore, the Quantile g-computation model (Qgc), random forest model (RFM), and bayesian kernel machine regression models (BKMR) were integrated to estimate the mixed effects of PFAS exposure on the incidence risk of BC. RESULTS: Exposures to specific PFAS components were positively associated with an increased incidence risk of breast cancer. By grouping the study population into different baseline menopausal statuses, PFHxS, PFNA, PFBA, PFUdA, PFOS, and PFDA demonstrated a similarly positive correlation with BC incidence risks. However, the increased incidence risks of BC associated with PFOA, PFOS, PFUdA, and 9CL-PF3ONS exposure were exclusively found in the premenopausal population. Both BKMR and Qgc revealed that exposure to mixed PFAS was associated with an increased risk of breast cancer, with Qgc specifically indicating an odds ratio (OR) of 2.21 (95% CI: 1.53, 3.19). Random forests showed that PFBA, PFOS, PFHxS, and PFDA emerged as predominant factors potentially influencing breast cancer incidence. CONCLUSION: Our findings suggest a strong association between PFAS exposure and the incidence of breast cancer. Premenopausal women should exercise more caution regarding PFAS exposure.

Serum folate and risk of disabling dementia: a community-based nested case-control study.

PURPOSE: The aim of this study was to examine associations between serum folate levels and risk of disabling dementia that required care under the national insurance (disabling dementia). METHODS: We performed a nested case-control study in a community-based cohort, the Circulatory Risk in Communities Study, involving 13,934 Japanese individuals aged 40-84 years at the baseline period of 1984-2005. Serum folate was measured in 578 cases of incident disabling dementia, and in 1,156 controls whose age (±1 years), sex, area of residence, and baseline year were matched with the cases. The diagnosis of disabling dementia was performed by attending physicians under the National Long-Term Care Insurance System in Japan. Conditional odds ratios of disabling dementia according to quintiles of serum folate were calculated using conditional logistic regression models. RESULTS: After a 20.8-year follow-up, serum folate was inversely associated with risk of disabling dementia. The respective multivariable odds ratios (95% CIs) were 0.71 (0.51-0.99), 0.76 (0.54-1.06), 0.70 (0.49-1.00), and 0.62 (0.43-0.90) for persons with the second, third, fourth, and highest quintiles of serum folate as compared with the lowest quintile (P for trend = 0.03). A similar association was observed for dementia with or without stroke. CONCLUSION: In this nested case-control study with a long follow-up, low serum folate levels were associated with an increased risk of disabling dementia among Japanese individuals.

ß-hydroxybutyrate and mitochondria mediate the association between medium-chain fatty acids, DHA and mild cognitive impairment: a nested case-control study.

BACKGROUND: Medium-chain fatty acids (MCFAs) and docosahexaenoic acid (DHA) could affect the occurrence of mild cognitive impairment (MCI). ß-hydroxybutyrate (BHB), mitochondrial DNA copy number (mtDNAcn) and mitochondrial DNA (mtDNA) deletions might be their potential mechanisms. This study aimed to explore the relationship between MCFAs, DHA and MCI, and potential mechanisms. METHODS: This study used data from Tianjin Elderly Nutrition and Cognition (TENC) cohort study, 120 individuals were identified with new onset MCI during follow-up, 120 individuals without MCI were selected by 1:1 matching sex, age, and education levels as the control group from TENC. Conditional logistic regression analysis and mediation effect analysis were used to explore their relationship. RESULTS: Higher serum octanoic acid levels (OR: 0.633, 95% CI: 0.520, 0.769), higher serum DHA levels (OR: 0.962, 95% CI: 0.942, 0.981), and more mtDNAcn (OR: 0.436, 95% CI: 0.240, 0.794) were associated with lower MCI risk, while more mtDNA deletions was associated with higher MCI risk (OR: 8.833, 95% CI: 3.909, 19.960). Mediation analysis suggested that BHB and mtDNAcn, in series, have mediation roles in the association between octanoic acid and MCI risk, and mtDNA deletions have mediation roles in the association between DHA and MCI risk. CONCLUSION: Higher serum octanoic acid and DHA levels were associated with lower MCI risk. Octanoic acid could affect the incidence of MCI through BHB, then mitochondria function, or through mitochondria function, or directly. Serum DHA level could affect the incidence of MCI through mitochondria function, or directly.

Impact of Awareness of Sexual Partners' HIV Serostatus on the HIV Acquisition among Men Who Have Sex with Men in Guangzhou, China: A Nested Case-Control Study.

This study aimed to investigate the impact of sexual partners' HIV serostatus awareness on the HIV acquisition among men who have sex with men (MSM) in Guangzhou, China. A nested case-control study was conducted based on a prospective cohort of MSM in Guangzhou. Within the cohort, individuals who underwent HIV seroconversion were identified as the case group, and each case was matched with four controls from the non-seroconverted participants. Information regarding the awareness of sexual partners' HIV serostatus over the preceding 6 months was gathered. Of the 161 participants, 36.0% were aware of the HIV serostatus of all their sexual partners. The practice of engaging in condomless anal sex with partners of unknown HIV serostatus and being aware of the HIV serostatus of only some casual partners were positively correlated with an elevated risk of acquiring HIV. Conversely, being fully aware of the HIV serostatus of all sexual partners, including regular ones, was associated with a diminished risk of HIV incidence. Regular communication with sexual partners regarding HIV testing outcomes, honest disclosure of one's own HIV serostatus, and refusal of sexual contact with partners of unknown HIV serostatus can potentially mitigate the risk of acquiring HIV among MSM.

Prevalence of diabetes and hospitalization due to poor glycemic control in people with bladder cancer or renal cell carcinoma in Sweden.

BACKGROUND: Bladder cancer (BC) and Renal cell carcinoma (RCC) are the most common urogenital cancers among both sexes, with a yearly global incidence of around 500 000 each. Both BC and RCC have been linked to diabetes. Poor glycemic control (malglycemia) is a serious consequence of diabetes and a possible consequence of systemic treatments used in BC and RCC. The objective of this study was to investigate the prevalence of diabetes and use of hospital-based care for malglycemia in people with BC or RCC. METHODS: This Swedish retrospective population-based register study used national health-data registers for longitudinal data on cancer incidence covering 15 years, use of hospital-based health care, and filled prescriptions of outpatient medications. Study endpoints included co-prevalence of diabetes in individuals with BC/RCC, healthcare resource utilization due to malglycemia, use of systemic corticosteroids, and changes in diabetes management for people with concomitant type 2 diabetes. RESULTS: We identified 36,620 and 15,581 individuals diagnosed with BC and RCC, respectively, between 2006 and 2019. The proportion of individuals registered with diabetes was 24% in BC and 23% in RCC. An association between BC/RCC and poor glycemic control was found, although the number of malglycemic events in hospital-based care were few (65/59 per 1000 individuals with diabetes and BC/RCC respectively with at least one event). An earlier switch to insulin-based diabetes management was observed in BC/RCC compared to matched individuals with type 2 diabetes but no cancer. The results also indicated an association between steroid treatment and poor glycemic control, and that systemic corticosteroids were more common among people with BC/RCC compared to diabetes controls. CONCLUSION: The high prevalence of diabetes and increased use of systemic corticosteroid treatment observed in this large national study highlights the need for specific clinical management, risk-assessment, and monitoring of individuals with BC/RCC and diabetes.

The risk of long-term opioid use among immigrants: a national registry-linkage study.

AIMS: We aimed to investigate the association between being an immigrant and long-term prescription opioid use in Norway in 2010-2019. METHODS: Nested case-control study. The cases were all persons 18 years of age or older with long-term opioid use - that is, the use of prescription opioids longer than 3 months (N=215,642). Cases were matched to four controls who filled at least one opioid prescription, but never developed long-term opioid use in the study period (N=862,568) on sex, age and year of starting long-term/short-term opioid use. Being an immigrant was defined as being born outside of Norway to two foreign-born parents and four foreign-born grandparents. Adjusting for socioeconomic variables and clinical confounders, analyses were stratified on three age groups (18-44 years, 45-67 years and ⩾68 years). RESULTS: For the youngest age group, being an immigrant was inversely associated with long-term opioid use (adjusted odds ratio 0.75; 95% confidence interval [0.72-0.77]) compared with being native-born people. For this age group, the odds ratio differed between people born in Africa (0.56 [0.52-0.62]), Central or South America (0.70 [0.62-0.79]), Europe outside the European Union (EU) (0.71 [0.65-0.77]), Asia including Turkey (0.80 [0.77-0.84]) and EU/European Economic Area (EEA) (0.81 [0.77-0.85]). For the middle age group, increased odds were found for immigrants versus natives (1.05 [1.02-1.08]) in particular for those born in North America (1.26 [1.13-1.40]) and the EU/EEA (1.13 [1.09-1.18]). There was no association in the oldest group. CONCLUSIONS: Compared with native-born people, immigrants had lower odds of long-term opioid use among younger adults, higher odds among middle-aged and similar odds among older adults.

Comorbidity increases the risk of pulmonary tuberculosis: a nested case-control study using multi-source big data.

BACKGROUND: Some medical conditions may increase the risk of developing pulmonary tuberculosis (PTB); however, no systematic study on PTB-associated comorbidities and comorbidity clusters has been undertaken. METHODS: A nested case-control study was conducted from 2013 to 2017 using multi-source big data. We defined cases as patients with incident PTB, and we matched each case with four event-free controls using propensity score matching (PSM). Comorbidities diagnosed prior to PTB were defined with the International Classification of Diseases-10 (ICD-10). The longitudinal relationships between multimorbidity burden and PTB were analyzed using a generalized estimating equation. The associations between PTB and 30 comorbidities were examined using conditional logistic regression, and the comorbidity clusters were identified using network analysis. RESULTS: A total of 4265 cases and 17,060 controls were enrolled during the study period. A total of 849 (19.91%) cases and 1141 (6.69%) controls were multimorbid before the index date. Having 1, 2, and ≥ 3 comorbidities was associated with an increased risk of PTB (aOR 2.85-5.16). Fourteen out of thirty comorbidities were significantly associated with PTB (aOR 1.28-7.27), and the associations differed by sex and age. Network analysis identified three major clusters, mainly in the respiratory, circulatory, and endocrine/metabolic systems, in PTB cases. CONCLUSIONS: Certain comorbidities involving multiple systems may significantly increase the risk of PTB. Enhanced awareness and surveillance of comorbidity are warranted to ensure early prevention and timely control of PTB.

Antipsychotic medications and severe sepsis in schizophrenia: A nested case-control study.

BACKGROUND: Sepsis constitutes a condition that involves life-threatening organ dysfunction induced by severe infection. This nested case-control study investigated risk factors for severe sepsis and whether antipsychotic use is associated with severe sepsis risk in patients with schizophrenia, a topic that has not been comprehensively explored in previous studies. METHODS: We selected 39,432 patients with schizophrenia aged between 15 and 65 years from Taiwan's Psychiatric Inpatient Medical Claims database for the period 2000-2012. The case group comprised patients with severe sepsis after their first psychiatric admission (n = 1382). The case and control groups were randomly matched (1:4) by age, sex and first psychiatric admission (year) and finally comprised 1382 and 5528 individuals, respectively. We employed multivariable conditional logistic regression to identify (1) risk factors (physical illnesses and nonpsychiatric medications) and (2) antipsychotic-severe sepsis associations. RESULTS: Higher numbers of psychiatric admissions and physical illnesses such as delirium, cerebrovascular disease and cancer were significantly associated with a higher risk of severe sepsis. Furthermore, severe sepsis was associated with the use of antithrombotic agents, systemic corticosteroids and agents targeting the renin-angiotensin system. Clozapine (adjusted risk ratio = 1.65) and quetiapine (adjusted risk ratio = 1.59) use were associated with an increased risk of severe sepsis. The use of more than one antipsychotic drug could further increase this risk. CONCLUSION: Several physical illnesses and nonpsychiatric medications increase the risk of severe sepsis in patients with schizophrenia. Specifically, clozapine or quetiapine use significantly increased the risk of severe sepsis in these patients.

Health expenditure trajectory and gastric cancer incidence in the National Health Insurance Senior Cohort: a nested case-control study.

BACKGROUND: Gastric cancer is the fourth most common cancer and highly prevalent in South Korea. As one of the predictors of gastric cancer, we focused on health utilization patterns and expenditures, as the surrogate variables of health conditions. This nested case-control study aimed to identify the association between health expenditure trajectory and incidence of gastric cancer. METHODS: Data from the National Health Insurance Service Senior Cohort of South Korea were used. Individuals diagnosed with gastric cancer (N = 14,873) were matched to a non-diagnosed group (N = 44,619) in a 1:3 ratio using a nested case-control design. A latent class trajectory analysis was performed to identify the patterns of health expenditure among the matched participants. Furthermore, conditional logistic regression analysis was conducted to examine the relationship between healthcare expenditure trajectories and gastric cancer incidence. RESULTS: Seven distinct health expenditure trajectories for five years were identified; consistently lowest (13.8%), rapidly increasing (5.9%), gradually increasing (13.8%), consistently second-highest (21.4%), middle-low (18.8%), gradually decreasing (13.1%), and consistently highest (13.2%). Compared to the middle-low group, individuals in the rapidly increasing [odds ratio (OR) = 2.11, 95% confidence interval (CI); 1.94-2.30], consistently lowest (OR = 1.40, 95% CI; 1.30-1.51), and gradually increasing (OR = 1.26, 95% CI; 1.17-1.35) groups exhibited a higher risk of developing gastric cancer. CONCLUSIONS: Our findings suggest that health expenditure trajectories are predictors of gastric cancer. Potential risk groups can be identified by monitoring health expenditures.

The impact of Renin-Angiotensin System Inhibitors on bone fracture risk: a nationwide nested case-control study.

BACKGROUND: The therapeutic efficacy of renin-angiotensin system inhibitors (RASi) in elderly patients with hypertension and at risk of fractures has been in the limelight because of accumulating evidence that localized RAS activation in bone tissue leads to osteoclastic bone resorption, resulting in osteoporosis. This study set out to investigate the association between RASi use and fracture incidence in a large cohort. METHODS: We employed a nested case-control design to investigate the association between RASi use and newly developed fractures. A case was defined as a patient newly diagnosed with a fracture between January 2004 and December 2015. We selected 1,049 cases and controls using 1:1 propensity score matching. Conditional logistic regression analysis was conducted to estimate the association between RASi exposure and fracture incidence. RESULTS: Overall, RASi usage was significantly associated with lower odds for fracture incidence (ever-users vs never-users: OR, 0.73; 95% CI, 0.59-0.91). We found that ARB-only users experienced fewer fractures than RASi-never users (OR, 0.65; 95% CI, 0.49-0.86), whereas ACEi-only users or ARB/ACEi-ever users did not. In subgroup analysis, RASi-ever users without cerebrovascular disease, those with a BMI exceeding 23, and statin exposure had significantly lower ORs. CONCLUSIONS: The present study established a significant association between RASi use and reduced fracture incidence, thus highlighting the potential clinical utility of RASi use as a preventive strategy in elderly patients at risk for osteoporotic fractures.