Exotic dried fruits caused Salmonella Agbeni outbreak with severe clinical presentation, Norway, December 2018 to March 2019.

We describe an outbreak of Salmonella Agbeni sequence type (ST)2009 infections in Norway. Between 31 December 2018 and 16 March 2019, 56 cases (33 female and 23 male; median age: 50 years, range: 2-91) were reported, of which 21 were hospitalised. Cases were defined as people living in Norway, with laboratory-confirmed infection with S. Agbeni ST2009 and cluster type (CT)2489, reported between 31 December 2018 and 30 March 2019. We conducted a case-control study, with three controls per case (matched by age, sex and municipality), using the Norwegian National Registry. Cases were more likely to have consumed a commercial mix of dried exotic fruits than controls (cases = 8, controls = 31; odds ratio: 50; 95% confidence interval: 3-2,437). The outbreak strain was confirmed by whole genome sequencing (WGS) and was isolated from the fruit mix consumed by cases, resulting in withdrawal from the market on 6 March 2019.The fruit mix consisted of fruits from different countries and continents. It was packed in Italy and distributed to several European countries, including Norway. However, no other countries reported cases. This outbreak highlights that dried fruits could represent a risk in terms of food-borne infections, which is of particular concern in ready-to-eat products.

Reporting of notifiable infectious diseases during the COVID-19 response. / Registrerte meldingspliktige smittsomme sykdommer under covid-19-responsen.

BACKGROUND: The Norwegian Surveillance System for Communicable Diseases (MSIS) is based on reporting of cases of 72 mandatory notifiable diseases by clinical microbiological laboratories and diagnosing physicians. The aim of our study was to investigate a potential temporal association between measures against COVID-19 in February-April 2020 and incidence of other infectious diseases reported to MSIS. MATERIAL AND METHOD: We compared the number of disease cases reported to MSIS during weeks 6-14 in 2020 with the median of cases reported in corresponding weeks during three previous years (2017-2019). RESULTS: Compared to the median of cases reported during corresponding weeks in three previous years, physicians and laboratories reported 47 % fewer cases (159 vs. 301) in week 12, 50 % fewer cases (131 vs. 261) in week 13, and 69 % fewer cases (77 vs. 252) in week 14. There was a reduction in the number of notifications of all included disease groups. INTERPRETATION: The observed decline in reporting of diseases other than COVID-19 may indicate a reduced risk of communicable diseases due to comprehensive advice and the requirement for social distancing. However, it is also possible that the sensitivity of the surveillance system was affected by increased resource use on COVID-19 cases management.

Are the current notification criteria for Lyme borreliosis in Norway suitable? Results of an evaluation of Lyme borreliosis surveillance in Norway, 1995-2013.

BACKGROUND: The approach to surveillance of Lyme borreliosis varies between countries, depending on the purpose of the surveillance system and the notification criteria used, which prevents direct comparison of national data. In Norway, Lyme borreliosis is notifiable to the Surveillance System for Communicable Diseases (MSIS). The current notification criteria include a combination of clinical and laboratory results for borrelia infection (excluding Erythema migrans) but there are indications that these criteria are not followed consistently by clinicians and by laboratories. Therefore, an evaluation of Lyme borreliosis surveillance in Norway was conducted to describe the purpose of the system and to assess the suitability of the current notification criteria in order to identify areas for improvement. METHODS: The CDC Guidelines for Evaluation of Surveillance Systems were used to develop the assessment of the data quality, representativeness and acceptability of MSIS for surveillance of Lyme borreliosis. Data quality was assessed through a review of data from 1996 to 2013 in MSIS and a linkage of MSIS data from 2008 to 2012 with data from the Norwegian Patient Registry (NPR). Representativeness and acceptability were assessed through a survey sent to 23 diagnostic laboratories. RESULTS: Completeness of key variables for cases reported to MSIS was high, except for geographical location of exposureThe NPR-MSIS linkage identified 1047 cases in both registries, while 363 were only reported to MSIS and 3914 were only recorded in NPR. A higher proportion of cases found in both registries were recorded as neuroborreliosis in MSIS (84.4 %) than those cases found only in MSIS (20.1 %). The trend (average yearly increase or decrease in reported cases) of neuroborreliosis in MSIS was not significantly different from the trend for all other clinical manifestations recorded in MSIS in negative binomial regression (p = 0.3). The 16 surveyed laboratories (response proportion 70 %) indicated differences in testing practices and low acceptability of the notification criteria. CONCLUSIONS: Given the challenges associated with diagnosing Lyme borreliosis, the selected notification criteria should be closely linked with the purpose of the surveillance system. Restricting reportable Lyme borreliosis to neuroborreliosis may increase validity, while a more sensitive case definition (potentially including erythema migrans) may better reflect the true burden of disease. We recommend revising the current notification criteria in Norway to ensure that they are unambiguous for clinicians and laboratories.

European public health policies for managing contacts of invasive meningococcal disease cases better harmonised in 2013 than in 2007.

In 2007, a European survey identified variation in country policies on public health management of invasive meningococcal disease (IMD). In 2009-10, the European Centre for Disease Prevention and Control (ECDC) published evidence-based guidance on IMD. We therefore surveyed again European countries to describe policies for managing IMD cases and contacts in 2013. We asked national IMD public health experts from 32 European countries to complete a questionnaire focusing on post-exposure prophylaxis (PEP) for IMD contacts and meningococcal vaccination. Proportions in 2007 and 2013 were compared using the chi-squared test. All 32 countries responded, with responses from two regions for Belgium and Italy; half stated having used ECDC guidance to update national recommendations. PEP was recommended to close contacts in 33 of 34 countries/regions, mainly ciprofloxacin for adults (29/32 countries) and rifampicin for children (29/32 countries). ECDC guidance for managing IMD contacts in airplanes was strictly followed by five countries/regions. Twenty-three countries/regions participated in both surveys. Compared with 2007, in 2013, more countries/regions recommended i) ceftriaxone for children (15/23 vs 6/20; p = 0.03), ii) PEP for all children in the same preschool group (8/23 vs 17/23; p = 0.02). More countries/regions recommended evidence-based measures for IMD public health management in 2013 than 2007. However, some discrepancies remain and they call for further harmonisation.

Cross-border surveillance differences: tick-borne encephalitis and lyme borreliosis in the Czech Republic and Poland, 1999-2008.

We compared neighbouring regions of the Czech Republic (CZ) and Poland (PL) situated within 100 km of the country border, in order to compare surveillance systems performance in measuring the burden of tick-borne diseases in both countries. We used routine surveillance notifications from 1999-2008 on tick-borne encephalitis (TBE) and Lyme borreliosis (LB). We assessed the crude risk ratio (RR) across the country border, and its estimates adjusted for both population density and the expected epidemiological gradient across the region, using negative binomial regression. The crude RR between CZ and PL was 7.43 (95% Cl 6.20-8.90) for TBE, and 1.80 (1.76-1.83) for LB. The adjusted RR for TBE increased from 4.47 in 1999-2001 to 10.01 in 2005-2008, but for LB decreased from 9.30 to 2.51 during the respective periods. Those results reflect possible differences in surveillance systems performance between the two countries, as the administrative boundaries cannot constitute a barrier for zoonotic diseases and no biological processes alone can explain such large differences in disease occurrence.

Toward rubella elimination in Poland: need for supplemental immunization activities, enhanced surveillance, and further integration with measles elimination efforts.

BACKGROUND: All Member States of the World Health Organization (WHO) European Region have endorsed rubella elimination and congenital rubella syndrome (CRS) prevention. However, Poland has continued high levels of reported rubella. METHODS: We reviewed rubella incidence in Poland since 1966 and analyzed national aggregated surveillance data from the period 2003-2008 and case-based data from 4 provinces from the period 2006-2008. We described CRS cases since 1997 and assessed maternal receipt of vaccine. We reviewed national vaccination coverage from 1992 through 2008. RESULTS: Since 1966, rubella outbreaks have occurred every 4-6 years in Poland. Aggregate and case-based data from the period 2003-2008 indicate that rubella virus transmission has occurred across wide age ranges (from <1 year to 60 years), with disproportionately higher percentage of cases among adolescent boys. Of 18 children with reported CRS cases from 1997 through 2008, 15 (83%) of their mothers had not been vaccinated. Measles-mumps-rubella dose 1 vaccination coverage ranged from 97% to 99%. CONCLUSIONS: Poland had the highest incidence of rubella in the WHO European Region in 2007 and 2008. Rubella occurs predominantly in age and sex cohorts historically not included in vaccination recommendations. The risk for CRS continues. To achieve rubella elimination, supplemental immunization activities among adolescent boys are needed, as is integration with measles elimination efforts.

Behavioural and Cognitive Attitudes of Paediatricians towards Influenza Self-Vaccination-Partial Mediation Model.

(1) Background: This study aims to analyse the attitudinal components influencing paediatricians' self-vaccination. (2) Methods: The national-cross survey was conducted among paediatricians involved in childhood vaccination within the immunisation program. (3) Results: A hypothetical model indicating the influence of cognitive and behavioural factors on influenza vaccination among paediatricians was verified based on a survey of Polish paediatricians. A simple mediation model, based on Triandis' Theory of Interpersonal Behaviour, reflects a relationship in which knowledge and beliefs about outcomes contribute to whether paediatricians vaccinate against influenza. (4) Conclusions: The presented research shows that the pro-vaccination behaviours of paediatricians are not only influenced by cognitive factors but also the behavioural components of attitudes, which are equally important. The conclusions point to the pivotal role of shaping both knowledge and understanding of the effectiveness of immunisation programmes in building the pro-vaccination attitudes of paediatricians. (5) Practical Implications: This is the first representative study of Polish paediatricians to demonstrate how their attitudes and behaviour are related to self-vaccination. Its conclusions allow policymakers to develop programmes to support effective measures against the spread of infectious diseases through the self-vaccination of medical professionals.

[Reliability of the cut-off value in the routine serodiagnosis of pertussis performed by the commercial ELISA assays]. / Ocena wiarygodnosci poziomu przeciwcial przyjmowanego za diagnostycznie znamienny w serodiagnostyce krztusca wykonywanej odczynem ELISA.

In clinical practise, serodiagnosis of pertussis is mostly based on single-sample serology using a single cut-off. The reliability of the cut-off value has the crucial influence for the sensitivity and specificity of the used tests. In this context we compared the value of cut-off used in two commercial ELISA kits (NovaLisa Bordetella pertussis-NovaTec and ELISA Bordetella pertussis ELISA-Virotech) with cut-off settled by calculation the IgA and IgG results from the 60 healthy Polish children and 100 blood donors (arithmetic mean plus 2 or 3 standard deviations). Our study indicates that IgA cutoff used in NovaTec ELISA, in contrary to Virotech ELISA, correspond better to the level x+3SD calculated in children sera and x+2SD calculated in adult blood donors sera. The value of IgG cut-off used in Virotech ELISA was lower about 20% and 30% from the cut-off settled by us respectively on the level ofx+2SD and x+3SD in all tested sera. The most inadequate value had the IgG cut-offused in NovaTec ELISA, which was over three times lower than mean cut-off value settled by calculation results from the sera obtained from healthy children and blood donors. This low cut-off value established by the NovaTec was the reason that 23.3% of healthy children and 55.0% of blood donors have the IgG antibodies on the diagnostic significant level. Our data suggest that commercial ELISAs need further improvement and standardization.

Etiology of measles suspect cases reported in 2006-2007 in Poland.

To achieve measles elimination, an efficient surveillance system for rash illnesses is necessary. The aim of the present study was to ascertain which viruses, other than measles, are causing measles-like illnesses (MLIs) in Poland. Serum samples (n=278) collected from MLI cases and submitted to the National Reference Laboratory during 2006-2007 were investigated for anti-measles (MeV), rubella (RUBV), parvovirus B19 (B19V), Epstein-Barr (EBV) and herpesvirus type-6 (HHV-6) IgM presence. Age was strongly associated with MLIs etiology. In the youngest age group, 0-4 years, MeV and HHV-6 infection were prevailing, while in group of 5-9 years--RUBV and B 19V. Measles was confirmed more often in patients with high fever (p < 0.001) and with rash lasting longer than 5 days (p < 0.001). The type of rash was not significantly associated with MeV infection. Our results strongly suggest that according to WHO EURO strategic plan, Poland is close to elimination phase. High number of MLIs were caused by pathogens other than measles. Addition of anti-B 19V IgM testing to routine MLIs screening protocol may improve system performance in the more advanced stages of measles elimination.

[Sources of information and knowledge on childhood immunisations among Polish parents]. / Zródla informacji oraz wiedza rodziców na temat szczepien ochronnych w Polsce.

The aim of the study was to obtain information on parents' knowledge about mandatory and recommended vaccinations in Poland. Computer-assisted telephone interviews (CATI) method was used. The interviews were collected from parents who had children aged < or = 3 years. Two-stage sampling was used: first, a list of 3,000 households with children < or = 3 years was quota-selected from a consumer database collecting contact information from 95% mothers during deliveries; in the second stage, random digit dialling was used to attempt the interview with parents. The questionnaire applied was based on the survey developed by UK Department of Health. A total of 1045 interviews were collected, 960 from mothers, and 85 from fathers. The response rate was 77%. Mean age of parents was 28.9. Most parents (72%) had secondary or lower level of education. General practitioners (about 90% respondents) were found the most important, and the most reliable source of information for parents. Media (66%), including Internet (18%), were the second main source of theirs knowledge, but they were not considered as reliable source. Parental knowledge on obligatory vaccinations included in the childhood immunization schedule was found to be very low. Only 30% and 5% of respondents spontaneously recognized polio and Hib vaccines, respectively mandatory. The largest proportion of respondents indicated hepatitis B (46%) and tuberculosis (45%) as serious illness, and only 22% and 23% considered diphteria, and measles as serious diseases. Poor knowledge on childhood immunisations among Polish parents needs to be addressed by improvement of reliable information on vaccines and vaccine safety.

[Parental attitudes towards childhood immunisations in Poland]. / Postawy rodziców wobec szczepien ochronnych w Polsce.

The aim of the study was to obtain information on parents' attitudes towards vaccinations included in the childhood immunisation schedule. Computer-assisted telephone interviews (CATI) method was used. The interviews were collected from parents who had children aged three years old. Two-stage sampling was used: firstly, a list of 3,000 households with children < 3 years old was quota-selected from a consumer database collecting contact information from 95% mothers during deliveries. Random digit dialling was used to attempt the interview with parents. The 40-item questionnaire was based on the questionnaire developed by UK Department of Health. Overall, the perception of routine, mandatory immunization of children was positive. Only 17 parents (1.6%) refused the vaccination which had been offered, and 398 parents (38.0%) paid for a vaccine recommended for their child. In general, parents believed that immunisations were important for protecting the society against infectious diseases, although they found some problems in the way vaccines were delivered. Approximately half of respondents thought that vaccination against many diseases was harmful. In terms of perception of the risk related to vaccines parents were less confident in the currently introduced vaccines and those which protect against diseases rarely seen in the population. Pneumococcal vaccine was considered as risky by 27 persons (2.6%), and polio vaccine by 17 (1.6%). Greater concern about the safety of vaccines was expressed by older parents, residents of towns and highly educated individuals. Systematic monitoring of parents' attitudes towards vaccination would help to address public health actions more adequately.

Exploring factors improving support for vaccinations among Polish primary care physicians.

In Poland, primary care physicians are the most used and most trusted source of information on immunisation. We aimed to explore factors influencing support for vaccinations among physicians employed in the childhood immunisation programme, in order to inform education of healthcare workers and programme organization. In June-July 2017, we carried out a national cross-sectional survey of physicians working in randomly selected primary healthcare practices, and interviewed them by telephone. We assessed support for vaccinations using an ordinal scale (0-6) comprised of three equally weighted questions on the respondent support of the programme and vaccination of self and family. We also created a scale (0-3) based on correct answers to vaccination myths. We used ordered logistic regression to investigate factors independently influencing support for vaccinations, reporting the proportional odds ratios and 95% confidence intervals for one unit increase in the support score. Of 2,609 respondents contacted, we interviewed 500 (19%). The median vaccination support score (0-6) was 5 (IQR 2). After adjusting for other variables, we did not find significant effects of sex, medical specialty, adhering to recommendations, attending a conference in previous year, using non-scientific sources of information and self-assessed knowledge on vaccination support score. Age over 60 years, correctly addressing vaccination myths and use of one or more than one scientific sources of knowledge, significantly improved support for vaccinations (aOR = 1.97, 1.57, 3.09 and 2.68, respectively). We recommend to increase the amount, quality and accessibility of evidence-based educational materials for primary care physicians working with childhood immunisations.

High overall confidence in childhood vaccination in Norway, slightly lower among the unemployed and those with a lower level of education.

In Norway, childhood immunisation is offered on voluntary basis, free of charge and is delivered through trained nurses at > 650 child health centres and school health services. Maintaining high confidence in the vaccination programme is key to sustaining high vaccine uptake. We aimed to investigate confidence in childhood vaccination in the general population and to identify determinants for lower confidence. In 2017 and 2018, Statistics Norway asked questions on confidence in childhood vaccination (to all respondents) and children's vaccination history (to parents) in their routine cross-sectional survey. Respondents reported their level of agreement on a five-point Likert scale. Using a weighted analysis we calculated proportions agreeing [95% confidence interval] by respondent characteristics. Overall, 2169 individuals participated (54% response). 95.8% [94.8-96.7] answered that vaccination is important, 93.4% [92.2-94.4] thought that vaccines are safe, 96.0% [95.0-96.8] thought that vaccines are effective and for 93.4% [92.2-94.4] vaccination was compatible with their basic values. Those with lower level of education expressed lower confidence in vaccination due to conflict with their basic values (88.2% [84.7-91.0] answered positively). Those unemployed expressed lower confidence due to conflict with their basic values (81.9% [71.8-88.9]) and because of concerns about vaccines' safety (83.5% [73.7-90.1]). 96.3% [94.3-97.6] of parents (n = 580) had their children fully vaccinated, despite that one fifth answered that they at least once have had doubts on whether or not to vaccinate their children. There is high confidence in childhood vaccination in Norway. Those with a lower level of education and the unemployed reported comparatively lower confidence. To maintain high confidence in childhood vaccination, we recommend maintaining the well-informed system with easily accessible vaccinations. Furthermore, we recommend maintaining surveillance of vaccine confidence, supplemented with targeted studies on subgroups who are less confident, express doubts and/or oppose vaccination. Those studies should inform communication strategies tailored to subgroups.

Genetic diversity of Francisella tularensis in Poland with comments on MLVA genotyping and a proposition of a novel rapid v4-genotyping.

We investigated the genotypes of Francisella tularensis (F. tularensis) strains isolated in Poland during the period 1953-2013 and studied their genetic relationship to F. tularensis strains isolated in other countries using MLVA. We examined the mosquito and tick samples collected in Poland for the presence of F. tularensis DNA using PCR. Our results revealed a high genetic diversity among the strains of F. tularensis collected from Poland, suggesting that the bacterium is commonly found in the environment. However, we did not detect F. tularensis DNA in ticks and mosquitoes, showing that the arthropod bites might not be the main source of infection. We also propose the application of a practical assay called v4-genotyping that can be directly performed on the clinical and environmental samples. In addition, we discovered genetic variations among Schu S4 reference strains used in various laboratories and showed that MLVA analysis should not be based on amplicon sizes only because point mutations occurring within the MLVA loci might not always be manifested by a change in the amplicon size.

[Measles in Poland in 2007]. / Odra w Polsce w 2007 roku.

In Poland 40 measles cases were registered in 2007 (0.1 per 100,000 population). The most affected age group were infants (incidence 1.32 per 100,000 population) and 6-year olds (0.81). 18 measles cases (45%) were hospitalized, no deaths were recorded. Poland participates in the WHO Measles Elimination Strategy. Presently, the most important is the maintenance of a sensitive and timely surveillance of measles and measles-compatible cases, with serologic testing of one suspect case per 100,000 population. The performance of the surveillance system was insufficient with only 152 measles-compatible cases reported in 2007 (38% of expected reports). Serologic confirmation of cases was also insufficient, with 29 cases (73%) confirmed by IgM ELISA test. These results indicate the need to maintain the high immunisation coverage and improve measles surveillance system.

[Rubella in Poland in 2007]. / Rózyczka w Polsce w 2007 roku.

In Poland, 22,891 cases of rubella were registered in 2007 (incidence 60.1 per 100,000 population), of which 152 (0.7%) cases were laboratory confirmed. No cases of congenital rubella syndrome were reported. The incidence in men (88.7) was 62.5% higher than in women (33.3). The highest incidence was observed in children aged 6 and 7 years (492.8 and 540.5, respectively). No rubella deaths were registered. An improvement in diagnostic certainty of reported cases is necessary to assess the impact of 2-dose immunization implemented in 2003 on rubella epidemiology in Poland.

[Meningitis and encephalitis in Poland in 2007]. / Zapalenia opon mózgowo-rdzeniowych i zapalenia mózgu w Polsce w 2007 roku.

In Poland, 3,361 cases of neuroinfections were reported in 2007, of which 1,078 had bacterial etiology, 1,717--viral aetiology, and 566--other or unknown origin. The etiological agent was determined in 611 (57%) cases of bacterial neuroinfections. Among them N. meningitidis was found in 224 cases, H. influenzae type B (Hib) in 35 cases and S. pneumoniae in 161 cases. An increasing trend in meningococcal infections incidence has been observed in 2007, and a substantial decrease ofHib incidence, related to increasing vaccination coverage. Viral neuroinfections incidence in 2007 increased compared to year 2006. Among confirmed cases, there were 233 cases oftick-borne encephalitis. Most of the cases were reported from endemic areas of north-eastern part of the country.

[Detection of TBEV RNA in ticks as a tool for valuation of endemic area wide and sensitivity of TBE surveillance]. / Obecnosc RNA wirusa kleszczowego zapalenia mózgu w kleszczach Ixodes ricinus jako narzedzie oceny zasiegu obszarów endemicznych i czulosci nadzoru nad zachorowaniami na KZM.

In this study we present the nested RT-PCR strategy designed for detection of TBEV RNA in ticks Ixodes ricinus. The presented nested RT-PCR method using 2 different primer pairs specific primers for NS5 gene provides specific TBEV cDNA detectable by electroforesis in agarose gel. Of the 177 polls of ticks investigated, TBEV RNA was detected in 14, which accounts for 7.9% of all pools. We confront the PCR results of tested ticks to routine surveillance data. The obtained results showed that the TBEV RNA is detectable in ticks collected in areas in Poland, which are defined as an non-endemic. The nested RT-PCR method can be used as a tool of epidemiological surveillance as well as for screening of occurrence of circulating TBEV.

Pneumococcal meningitis before the introduction of 10-valent pneumococcal conjugate vaccine into the National Childhood Immunization Program in Poland.

BACKGROUND: Poland introduced the 10-valent conjugate pneumococcal vaccine (PCV10) into the childhood immunization program in January 2017. During previous decades, considerable changes had occurred in the surveillance system for invasive pneumococcal disease. Therefore, to provide baseline data on pneumococcal diseases before PCV10 introduction, we evaluated the epidemiology of pneumococcal meningitis (PM), the only syndrome monitored consistently since 1970. METHODS: Based on laboratory-confirmed cases reported during 2005-2015, we calculated the reported rates, serotypes distribution and antimicrobial resistance of pneumococcal meningitis isolates. Data from the mandatory national surveillance system was linked with data on cerebrospinal fluid isolates submitted to the National Reference Centre for Bacterial Meningitis. We used negative binomial regression with Newey West method to test for trend in rates of pneumococcal meningitis notified during 2005-2015 and Chi-squared test to assess changes in the serotype distribution from 2008-2011 to 2012-2015. RESULTS: From 2005 to 2015, the overall reported incidence of PM increased from 0.21 to 0.47 cases per 100,000 population, average yearly increase of 7% (rate ratio 1.07; 95% CI 1.06-1.08). The increase was primarily due to annual increase of 3% (1.02-1.05) among 15-49 years of age, 12% (95% CI: 1.10-1.13) among 50-64 years of age, 18% (95% CI: 1.16-1.19) among persons 65-74 years of age and 9% (95% CI 1.07-1.10) among persons ≥75 years of age. In children <5 years of age, serotypes included in PCV10 and PCV13 accounted for 75% and 80% of reported isolates, respectively. From 2008-2011 to 2012-2015, the proportion of PM cases caused by PCV10 serotypes decreased from 52% to 41% (p < 0.01). Overall, 28% of isolates were resistant to penicillin and 13% were non-susceptible to cefotaxime. CONCLUSIONS: The introduction of PCV10 into national immunization program may have considerable impact on disease burden, especially on number of cases caused by isolates non-susceptible to antimicrobials.

Association between exposure to a mixture of phenols, pesticides, and phthalates and obesity: Comparison of three statistical models.

BACKGROUND: The evaluation of the chemical impact on human health is usually constrained to the analysis of the health effects of exposure to a single chemical or a group of similar chemicals at one time. The effects of chemical mixtures are seldom analyzed. In this study, we applied three statistical models to assess the association between the exposure to a mixture of seven xenobiotics (three phthalate metabolites, two phenols, and two pesticides) and obesity. METHODS: Urinary levels of environmental phenols, pesticides, and phthalate metabolites were measured in adults who participated in the U.S.-based National Health and Nutrition Examination Survey (NHANES) from 2013 to 2014. Body examination was conducted to determine obesity. We fitted multivariable models, using generalized linear (here both logistic and linear) regression, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) models to estimate the association between chemical exposures and obesity. RESULTS: Of 1269 individuals included in our final analysis, 38.5% had general obesity and 58.0% had abdominal obesity. In the logistic regression model established for each single chemical, bisphenol S (BPS), mono (carboxyoctyl) phthalate (MCOP), and mono (2-ethyl-5-carboxypentyl) phthalate (MECPP) were associated with both general and abdominal obesity (fourth vs. first quartile). In linear regression, MCOP was associated with BMI and waist circumference. In WQS regression analysis, the WQS index was significantly associated with both general obesity (OR = 1.63, 95% CI: 1.21-2.20) and abdominal obesity (OR = 1.66, 95% CI: 1.18-2.34). MCOP, bisphenol A (BPA), bisphenol S (BPS), and mono ethyl phthalate (MEP) were the most heavily weighing chemicals. In BKMR analysis, the overall effect of mixture was significantly associated with general obesity when all the chemicals were at their 60th percentile or above it, compared to all of them at their 50th percentile. MCOP, BPA, and BPS showed positive trends. By contrast, MECPP showed a flat and modest inverse trend. CONCLUSION: When comparing results from these three models, MCOP, BPA, and BPS were identified as the most important factors associated with obesity. We recommend estimating the joint effects of chemical mixtures by applying diverse statistical methods and interpreting their results together, considering their advantages and disadvantages.