A Bayesian spatiotemporal approach to modelling arboviral diseases in Mexico

BACKGROUND

The objective of this study was to evaluate the spatial and temporal patterns of disease prevalence clusters of dengue (DENV), chikungunya (CHIKV) and Zika (ZIKV) virus and how socio-economic and climatic variables simultaneously influence the risk and rate of occurrence of infection in Mexico.

METHODS

To determine the spatiotemporal clustering and the effect of climatic and socio-economic covariates on the rate of occurrence of disease and risk in Mexico, we applied correlation methods, seasonal and trend decomposition using locally estimated scatterplot smoothing, hotspot analysis and conditional autoregressive Bayesian models.

RESULTS

We found cases of the disease are decreasing and a significant association between DENV, CHIKV and ZIKV cases and climatic and socio-economic variables. An increment of cases was identified in the northeastern, central west and southeastern regions of Mexico. Climatic and socio-economic covariates were significantly associated with the rate of occurrence and risk of the three arboviral disease cases.

CONCLUSION

The association of climatic and socio-economic factors is predominant in the northeastern, central west and southeastern regions of Mexico. DENV, CHIKV and ZIKV cases showed an increased risk in several states in these regions and need urgent attention to allocate public health resources to the most vulnerable regions in Mexico.

Physician-level determinants of HCV screening during pregnancy in a U.S. sample

PURPOSE

The purpose of this study was to assess the association between select determinants and HCV screening guideline adherence among physicians who provide prenatal care.

RESEARCH QUESTION

What factors may act as determinants of guideline adherence to HCV screening among physicians who provide prenatal care?

METHODS

We surveyed a national sample of physicians who provided prenatal care in 2021. The survey included questions from the Clinician Guideline Determinant (CGD) questionnaire, demographic characteristics, and medical practice characteristics. We estimated odds ratios and 95% confidence intervals (CIs) using semi-Bayesian logistic regression for the association between determinants and guideline adherence.

RESULTS

Participants included 224 physicians in the United States who reported providing prenatal care. Most physicians practiced in private practice (65%) and the majority were members of the American College of Obstetricians and Gynecologists (ACOG; 91%). Less than half (43%; 95% CI: 36%-49%) of physicians reported regular use of the HCV screening guideline. Physicians who reported general knowledge about HCV (OR = 9.0, 95% CI 3.1-30) or endorsed agreement with ease of implementation (OR = 8.0, 95% CI 2.7-25) had higher odds of adherence to the HCV screening guideline.

CONCLUSION

Our study suggests that less than half of practicing prenatal care physicians adhere to HCV screening guidelines for pregnant patients. Our results may be useful as a preliminary screening of select determinants of guideline use for further investigation.

Moderation effects of serotype on dengue severity across pregnancy status in Mexico

BACKGROUND

Pregnancy increases a woman's risk of severe dengue. To the best of our knowledge, the moderation effect of the dengue serotype among pregnant women has not been studied in Mexico. This study explores how pregnancy interacted with the dengue serotype from 2012 to 2020 in Mexico.

METHOD

Information from 2469 notifying health units in Mexican municipalities was used for this cross-sectional analysis. Multiple logistic regression with interaction effects was chosen as the final model and sensitivity analysis was done to assess potential exposure misclassification of pregnancy status.

RESULTS

Pregnant women were found to have higher odds of severe dengue [1.50 (95% CI 1.41, 1.59)]. The odds of dengue severity varied for pregnant women with DENV-1 [1.45, (95% CI 1.21, 1.74)], DENV-2 [1.33, (95% CI 1.18, 1.53)] and DENV-4 [3.78, (95% CI 1.14, 12.59)]. While the odds of severe dengue were generally higher for pregnant women compared with non-pregnant women with DENV-1 and DENV-2, the odds of disease severity were much higher for those infected with the DENV-4 serotype.

CONCLUSION

The effect of pregnancy on severe dengue is moderated by the dengue serotype. Future studies on genetic diversification may potentially elucidate this serotype-specific effect among pregnant women in Mexico.

Sex Difference in OA: Should We Blame Estrogen?

Osteoarthritis (OA) is a leading cause of chronic pain and disability, not only in the United States but also worldwide. The burden of OA is higher in women than in men. Estrogen as a possible explanation for observed sex differences in OA has not been definitively established. The purpose of this review was to summarize the results from studies of estrogen, estrogen depletion and treatment, and their impact on knee, hip, hand, and spine OA. We conducted a targeted review of the literature using PubMed. Although several studies show that hormone replacement therapy has the potential to be protective of OA for some joints, there are studies that showed no protective effect or even adverse effect. Taken together, the evidence for the protective effect of estrogen therapy depends on OA joint, OA outcome, and study design. Although this area has been studied for decades, more exclusively since the 1990s, there is a lack of high-quality experimental research in this topic. The lack of definitive conclusion on whether estrogen can play a role in the development in OA of either the knee, hip, spine, or hand is often in part due to the noncomparability of studies existing within the literature. Differences in diagnostic criteria, imaging modalities, populations studied, study designs, and outcome measures, as well as random error, have all contributed to inconclusive evidence. Future research on the role of estrogen in OA is needed, particularly as global demographic shifts in increasing overweight/obesity prevalence and ageing populations may contribute to widening OA-related health inequalities.

Country-Level Governance Indicators as Predictors of COVID-19 Morbidity, Mortality, and Vaccination Coverage: An Exploratory Global Analysis

As the COVID-19 pandemic continues to affect all countries across the globe, this study seeks to investigate the relationship between nations' governance, COVID-19 national data, and nation-level COVID-19 vaccination coverage. National-level governance indicators (corruption index, voice and accountability, political stability, and absence of violence/terrorism), officially reported COVID-19 national data (cases, death, and tests per one million population), and COVID-19 vaccination coverage was considered for this study to predict COVID-19 morbidity and mortality. Results indicate a strong relationship between nations' governance and officially reported COVID-19 data. Countries were grouped into three clusters using only the governance data: politically stable countries, average countries or "less corrupt countries," and corrupt countries or "more corrupt countries." The clusters were then tested for significant differences in reporting various aspects of the COVID-19 data. According to multinomial regression, countries in the cluster of politically stable nations reported significantly more deaths, tests per one million, total cases per one million, and higher vaccination coverage compared with nations both in the clusters of corrupt countries and average countries. The countries in the cluster of average nations reported more tests per one million and higher vaccination coverage than countries in the cluster of corrupt nations. Countries included in the corrupt cluster reported a lower death rate and morbidity, particularly compared with the politically stable nations cluster, a trend that can be attributed to poor governance and inaccurate COVID-19 data reporting. The epidemic evaluation indices of the COVID-19 cases demonstrate that the pandemic is still evolving on a global level.

Spatio-temporal dynamics of three diseases caused by Aedes-borne arboviruses in Mexico

Background

The intensity of transmission of Aedes-borne viruses is heterogeneous, and multiple factors can contribute to variation at small spatial scales. Illuminating drivers of heterogeneity in prevalence over time and space would provide information for public health authorities. The objective of this study is to detect the spatiotemporal clusters and determine the risk factors of three major Aedes-borne diseases, Chikungunya virus (CHIKV), Dengue virus (DENV), and Zika virus (ZIKV) clusters in Mexico.

Methods

We present an integrated analysis of Aedes-borne diseases (ABDs), the local climate, and the socio-demographic profiles of 2469 municipalities in Mexico. We used SaTScan to detect spatial clusters and utilize the Pearson correlation coefficient, Randomized Dependence Coefficient, and SHapley Additive exPlanations to analyze the influence of socio-demographic and climatic factors on the prevalence of ABDs. We also compare six machine learning techniques, including XGBoost, decision tree, Support Vector Machine with Radial Basis Function kernel, K nearest neighbors, random forest, and neural network to predict risk factors of ABDs clusters.

Results

DENV is the most prevalent of the three diseases throughout Mexico, with nearly 60.6% of the municipalities reported having DENV cases. For some spatiotemporal clusters, the influence of socio-economic attributes is larger than the influence of climate attributes for predicting the prevalence of ABDs. XGBoost performs the best in terms of precision-measure for ABDs prevalence.

Conclusions

Both socio-demographic and climatic factors influence ABDs transmission in different regions of Mexico. Future studies should build predictive models supporting early warning systems to anticipate the time and location of ABDs outbreaks and determine the stand-alone influence of individual risk factors and establish causal mechanisms.

Trends in Diet Quality by Race/Ethnicity among Adults in the United States for 2011-2018

This study aimed to investigate time trends in diet quality and the consumption of major food groups and nutrients by race/ethnicity among adults in the United States. Dietary data from 19,192 adults aged ≥ 20 years from four National Health and Nutrition Survey (NHANES) cycles (2011-2018) were included. The Healthy Eating Index (HEI) 2015 scores (range: 0-100; higher scores indicate better diet quality) and dietary consumption of food groups and nutrients were estimated for each cycle. Linear regression was used to test trends. For the overall population, the estimated overall HEI-2015 scores significantly decreased (p for trend = 0.011). However, decreases were observed in the estimated consumption of added sugars and total carbohydrates, while the estimated consumption of soy products and polyunsaturated fatty acids was significantly increased. A significant decrease in overall HEI-2015 score was observed in the non-Hispanic white group, but not in other racial/ethnic groups. Decreases in added sugar intake were found in the non-Hispanic black and Hispanic groups; sodium intake significantly decreased in the non-Hispanic Asian group. From 2011 to 2018, there was a decrease in estimated overall diet quality in US adults; however, there were improvements in certain nutrients and dietary components. Nevertheless, disparities in diet quality exist among racial/ethnic groups.

The human toll and humanitarian crisis of the Russia-Ukraine war: the first 162 days

BACKGROUND

We examined the human toll and subsequent humanitarian crisis resulting from the Russian invasion of Ukraine, which began on 24 February 2022.

METHOD

We extracted and analysed data resulting from Russian military attacks on Ukrainians between 24 February and 4 August 2022. The data tracked direct deaths and injuries, damage to healthcare infrastructure and the impact on health, the destruction of residences, infrastructure, communication systems, and utility services - all of which disrupted the lives of Ukrainians.

RESULTS

As of 4 August 2022, 5552 civilians were killed outright and 8513 injured in Ukraine as a result of Russian attacks. Local officials estimate as many as 24 328 people were also killed in mass atrocities, with Mariupol being the largest (n=22 000) such example. Aside from wide swaths of homes, schools, roads, and bridges destroyed, hospitals and health facilities from 21 cities across Ukraine came under attack. The disruption to water, gas, electricity, and internet services also extended to affect supplies of medications and other supplies owing to destroyed facilities or production that ceased due to the war. The data also show that Ukraine saw an increase in cases of HIV/AIDS, tuberculosis, and Coronavirus (COVID-19).

CONCLUSIONS

The 2022 Russia-Ukraine War not only resulted in deaths and injuries but also impacted the lives and safety of Ukrainians through destruction of healthcare facilities and disrupted delivery of healthcare and supplies. The war is an ongoing humanitarian crisis given the continuing destruction of infrastructure and services that directly impact the well-being of human lives. The devastation, trauma and human cost of war will impact generations of Ukrainians to come.

Community acceptability of dengue fever surveillance using unmanned aerial vehicles: A cross-sectional study in Malaysia, Mexico, and Turkey

Surveillance is a critical component of any dengue prevention and control program. There is an increasing effort to use drones in mosquito control surveillance. Due to the novelty of drones, data are scarce on the impact and acceptance of their use in the communities to collect health-related data. The use of drones raises concerns about the protection of human privacy. Here, we show how willingness to be trained and acceptance of drone use in tech-savvy communities can help further discussions in mosquito surveillance. A cross-sectional study was conducted in Malaysia, Mexico, and Turkey to assess knowledge of diseases caused by Aedes mosquitoes, perceptions about drone use for data collection, and acceptance of drones for Aedes mosquito surveillance around homes. Compared with people living in Turkey, Mexicans had 14.3 (p < 0.0001) times higher odds and Malaysians had 4.0 (p = 0.7030) times the odds of being willing to download a mosquito surveillance app. Compared to urban dwellers, rural dwellers had 1.56 times the odds of being willing to be trained. There is widespread community support for drone use in mosquito surveillance and this community buy-in suggests a potential for success in mosquito surveillance using drones. A successful surveillance and community engagement system may be used to monitor a variety of mosquito spp. Future research should include qualitative interview data to add context to these findings.

The Disproportionate Impact of COVID-19 among Undocumented Immigrants and Racial Minorities in the US

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for coronavirus disease 2019 (COVID-19), has had an unprecedented effect, especially among under-resourced minority communities. Surveillance of those at high risk is critical for preventing and controlling the pandemic. We must better understand the relationships between COVID-19-related cases or deaths and characteristics in our most vulnerable population that put them at risk to target COVID-19 prevention and management efforts. Population characteristics strongly related to United States (US) county-level data on COVID-19 cases and deaths during all stages of the pandemic were identified from the onset of the epidemic and included county-level socio-demographic and comorbidities data, as well as daily meteorological modeled observation data from the North American Regional Reanalysis (NARR), and the NARR high spatial resolution model to assess the environment. Advanced machine learning (ML) approaches were used to identify outbreaks (geographic clusters of COVID-19) and included spatiotemporal risk factors and COVID-19 vaccination efforts, especially among vulnerable and underserved communities. COVID-19 outcomes were found to be negatively associated with the number of people vaccinated and positively associated with age, the prevalence of cardiovascular disease, diabetes, and the minority population. There was also a strong positive correlation between unauthorized immigrants and the prevalence of COVID-19 cases and deaths. Meteorological variables were also investigated, but correlations with COVID-19 were relatively weak. Our findings suggest that COVID-19 has had a disproportionate impact across the US population among vulnerable and minority communities. Findings also emphasize the importance of vaccinations and tailored public health initiatives (e.g., mask mandates, vaccination) to reduce the spread of COVID-19 and the number of COVID-19 related deaths across all populations.

Modern treatment of tibial shaft fractures: Is there a role today for closed treatment?

PURPOSE

The decision to attempt closed treatment on tibial shaft fractures can be challenging. At our institution, we attempt treatment of nearly all closed, isolated tibial shaft fractures. The purpose of this study was to report the results of 10 years of experience to develop a tool to identify patients for whom non-operative treatment of tibial shaft fractures may be a viable option METHOD: This was a retrospective review of patients with tibial shaft fracture seen at a level 1 trauma center over 10 years. Patients with closed, isolated injuries underwent sedation, closed reduction, long-leg casting, and outpatient follow-up. Patients were converted to surgery for inability to obtain or maintain acceptable alignment or patient intolerance. Radiographic characteristics and patient demographics were extracted. Logistic regression analysis was used to develop a model to predict which patient and injury characteristics determined success of nonoperative treatment.

RESULTS

334 patients were identified with isolated, closed tibial shaft fractures, who were reduced and treated in a long leg cast. 234 patients (70%) converted to surgical treatment due to inability to maintain alignment, patient intolerance, and nonunion. In a regression model, coronal/sagittal translation, sagittal angulation, fracture morphology, and smoking status were shown to be significant predictors of success of nonoperative treatment (p < 0.05). We developed a Tibial Operative Outcome Likelihood (TOOL) score designed to help predict success or failure of closed treatment. The TOOL score can be used to identify a subsegment of patients with injuries amenable to closed treatment (38% of injuries) with a nonoperative success rate over 60%.

CONCLUSION

Non-operative treatment of tibial shaft fractures is feasible, although there is a relatively high conversion rate to operative treatment. However, it is possible to use injury characteristics to identify a cohort of patients with a higher chance of success with closed treatment, which is potentially useful in a resource-constrained setting or for patients who wish to avoid surgery.

LEVEL OF EVIDENCE

Prognostic Level 3.

Knee Osteoarthritis, Potential Mediators, and Risk of All-Cause Mortality: Data From the Osteoarthritis Initiative

OBJECTIVE

To assess the relation of symptomatic knee osteoarthritis (OA), knee pain, and radiographic knee OA to All-cause mortality and to identify mediators in the causal pathway.

METHODS

Participants from the Osteoarthritis Initiative were divided into 4 groups: 1) symptomatic knee OA (i.e., both radiographic knee OA [Kellgren/Lawrence grade ≥2] and knee pain); 2) knee pain only; 3) radiographic knee OA only; and 4) neither radiographic knee OA nor knee pain. We examined the relation of knee OA status to All-cause mortality using a multivariable Cox proportional hazards model and assessed the extent to which the association was mediated by disability, physical component summary (PCS) and mental component summary (MCS) scores for quality of life (QoL), and use of oral pain-relief medications (i.e., nonsteroidal antiinflammatory drugs and opioids).

RESULTS

Among 4,796 participants, 282 died over the 96-month follow-up period. Compared with those with neither radiographic knee OA nor knee pain, multivariable-adjusted hazard ratios (HRs) of mortality were 2.2 (95% confidence interval [95% CI] 1.6-3.1) for symptomatic knee OA, 0.9 (95% CI 0.6-1.4) for knee pain only, and 2.0 (95% CI 1.4-2.9) for radiographic knee OA only, respectively. Indirect effects (HRs) of symptomatic knee OA on mortality via disability and PCS of QoL were 1.1 (95% CI 1.0-1.4) and 1.2 (95% CI 1.0-1.4), respectively. No apparent mediation effect was observed through either MCS of QoL or oral pain-relief medications use.

CONCLUSION

Participants with either symptomatic or radiographic knee OA were at an increased risk of All-cause mortality. Increased risk of mortality from symptomatic knee OA was partially mediated through its effect on disability and PCS of QoL.

Risk of venous thromboembolism in knee, hip and hand osteoarthritis: a general population-based cohort study

OBJECTIVES

Osteoarthritis is a leading cause of immobility and joint replacement, two strong risk factors for venous thromboembolism (VTE). We aimed to examine the relation of knee, hip and hand osteoarthritis to the risk of VTE and investigate joint replacement as a potential mediator.

METHODS

We conducted three cohort studies using data from The Health Improvement Network. Up to five individuals without osteoarthritis were matched to each case of incident knee (n=20 696), hip (n=10 411) or hand (n=6329) osteoarthritis by age, sex, entry time and body mass index. We examined the relation of osteoarthritis to VTE (pulmonary embolism and deep vein thrombosis) using a multivariable Cox proportional hazard model.

RESULTS

VTE developed in 327 individuals with knee osteoarthritis and 951 individuals without osteoarthritis (2.7 vs 2.0 per 1000 person-years), with multivariable-adjusted HR being 1.38 (95% CI 1.23 to 1.56). The indirect effect (HR) of knee osteoarthritis on VTE through knee replacement was 1.07 (95% CI 1.01 to 1.15), explaining 24.8% of its total effect on VTE. Risk of VTE was higher in hip osteoarthritis than non-osteoarthritis (3.3 vs 1.8 per 1000 person-years; multivariable-adjusted HR=1.83, 95% CI 1.56 to 2.13). The indirect effect through hip replacement yielded an HR of 1.14 (95% CI 1.04 to 1.25), explaining 28.1% of the total effect. No statistically significant difference in VTE risk was observed between hand osteoarthritis and non-osteoarthritis (1.5 vs 1.6 per 1000 person-years; multivariable-adjusted HR=0.88, 95% CI 0.67 to 1.16).

CONCLUSION

Our large population-based cohort study provides the first evidence that knee or hip osteoarthritis, but not hand osteoarthritis, was associated with an increased risk of VTE, and such an association was partially mediated through knee or hip replacement.

The impact of COVID-19 on globalization

Globalization has altered the way we live and earn a livelihood. Consequently, trade and travel have been recognized as significant determinants of the spread of disease. Additionally, the rise in urbanization and the closer integration of the world economy have facilitated global interconnectedness. Therefore, globalization has emerged as an essential mechanism of disease transmission. This paper aims to examine the potential impact of COVID-19 on globalization and global health in terms of mobility, trade, travel, and countries most impacted.

The effect of globalization were operationalized in terms of mobility, economy, and healthcare systems. The mobility of individuals and its magnitude was assessed using airline and seaport trade data and travel information. The economic impact was measured based on the workforce, event cancellations, food and agriculture, academic institutions, and supply chain. The healthcare capacity was assessed by considering healthcare system indicators and preparedness of countries. Utilizing a technique for order of preference by similarity to ideal solution (TOPSIS), we calculated a pandemic vulnerability index (PVI) by creating a quantitative measure of the potential global health. The pandemic has placed an unprecedented burden on the world economy, healthcare, and globalization through travel, events cancellation, employment workforce, food chain, academia, and healthcare capacity. Based on PVI results, certain countries were more vulnerable than others. In Africa, more vulnerable countries included South Africa and Egypt; in Europe, they were Russia, Germany, and Italy; in Asia and Oceania, they were India, Iran, Pakistan, Saudi Arabia, and Turkey; and for the Americas, they were Brazil, USA, Chile, Mexico, and Peru. The impact on mobility, economy, and healthcare systems has only started to manifest. The findings of this study may help in the planning and implementation of strategies at the country level to help ease this emerging burden.

Improvement in mental health following total hip arthroplasty: the role of pain and function

Background

Mental health has been shown to improve after total hip arthroplasty (THA). Little is known about the role of pain and function in this context. We assessed whether change in mental health was associated with improvement in pain and function 1 year post-surgery.

Methods

This prospective study included patients enrolled in a THA registry from 2010 to 2014. We examined the mental component score (MCS) before and 1 year post-surgery, and 1-year change, in association with Western Ontario McMaster Universities (WOMAC) pain and function scores. All scores were normalized, ranging from 0 to 100 (larger score indicating better outcome). Analyses were adjusted for potential confounders.

Results

Our study included 610 participants, of which 53% were women. Descriptive statistics are as follows: the average (SD) for age (years) was 68.5 (11.8), and for BMI was 26.9 (4.9). In addition, the MCS average (SD) at baseline was 44.7 (11.2), and at 1-year after THA was 47.5 (10.5). The average change from baseline to 1-year post-THA in MCS was 2.8 (95% CI: 1.9, 3.6), for an effect size of 0.26. As for the WOMAC pain score, the average change from baseline to 1-year post-THA was 44.2 (95%CI: 42.4, 46.0), for an effect size of 2.5. The equivalent change in WOMAC function was 38.1 (95% CI: 36.2, 40.0), for an effect size of 2.0. Results from multivariable analysis controlling for covariates showed that an improvement of 10 points in the 1-year change in pain score resulted in a 0.78 point (95%: CI 0.40, 1.26) increase in the 1-year change in MCS, whereas a 10-point improvement in the 1-year change in function was associated with a 0.94 point (95% CI: 0.56, 1.32) increase.

Conclusions

Mental health significantly improved from baseline to 1-year post-THA. Greater improvement in pain and function was associated with greater improvement in mental health 1 year post-THA.

Smoking Behavior Changes in the Early Rheumatoid Arthritis Period and Risk of Mortality During Thirty-Six Years of Prospective Followup

OBJECTIVE

To investigate whether rheumatoid arthritis (RA) diagnosis influences smoking behavior changes and whether these changes were associated with mortality.

METHODS

We identified an incident RA cohort in the Nurses' Health Study (NHS; 1976-2012). Behavioral data were collected through biennial questionnaires. We created a comparison cohort, matching RA cases to women without RA by age and calendar year at the index date of RA diagnosis. To investigate smoking behavior changes in the early RA period, sustained cessation was defined as permanently quitting within 4 years of the RA/index date. We used Cox regression to obtain hazard ratios (HRs) for mortality, comparing sustained smoking cessation to continued smoking.

RESULTS

Among 121,700 women in the NHS, we identified 938 with incident RA matched to 8,951 non-RA comparators. Among current smokers, 40.0% with RA permanently quit smoking in the early RA period, compared to 36.1% of comparators (odds ratio for sustained cessation 1.18 [95% confidence interval (95% CI) 0.88, 1.58]). There were 313 deaths (33.4%) in the RA cohort and 2,042 (22.8%) among comparators. Compared to continued smoking, sustained cessation was associated with similarly decreased mortality in both the RA (HR 0.58 [95% CI 0.33, 1.01]) and comparison (HR 0.47 [95% CI 0.39, 0.58]) cohorts. Women with RA had higher mortality for >5 post-RA pack-years (HR 3.67 [95% CI 2.80, 4.81]) than comparators with >5 post-index pack-years (HR 1.88 [95% CI 1.62, 2.17]; P < 0.001 for interaction; reference: ever-smoker non-RA women with 0 post-index pack-years).

CONCLUSION

Sustained smoking cessation within 4 years of RA diagnosis reduced mortality risk, with a similar effect observed among non-RA comparators. Smoking >5 pack-years after RA diagnosis significantly increased mortality beyond the risk of non-RA comparators.

Smoking paradox in the development of psoriatic arthritis among patients with psoriasis: a population-based study

OBJECTIVES

Smoking is associated with an increased risk of psoriatic arthritis (PsA) in the general population, but not among patients with psoriasis. We sought to clarify the possible methodological mechanisms behind this paradox.

METHODS

Using 1995-2015 data from The Health Improvement Network, we performed survival analysis to examine the association between smoking and incident PsA in the general population and among patients with psoriasis. We clarified the paradox using mediation analysis and conducted bias sensitivity analyses to evaluate the potential impact of index event bias and quantify its magnitude from uncontrolled/unmeasured confounders.

RESULTS

Of 6.65 million subjects without PsA at baseline, 225 213 participants had psoriasis and 7057 developed incident PsA. Smoking was associated with an increased risk of PsA in the general population (HR 1.27; 95% CI 1.19 to 1.36), but with a decreased risk among patients with psoriasis (HR 0.91; 95% CI 0.84 to 0.99). Mediation analysis showed that the effect of smoking on the risk of PsA was mediated almost entirely through its effect on psoriasis. Bias-sensitivity analyses indicated that even when the relation of uncontrolled confounders to either smoking or PsA was modest (both HRs=~1.5), it could reverse the biased effect of smoking among patients with psoriasis (HR=0.9).

CONCLUSIONS

In this large cohort representative of the UK general population, smoking was positively associated with PsA risk in the general population, but negatively associated among patients with psoriasis. Conditioning on a causal intermediate variable (psoriasis) may even reverse the association between smoking and PsA, potentially explaining the smoking paradox for the risk of PsA among patients with psoriasis.

Symptoms of Knee Instability as Risk Factors for Recurrent Falls

OBJECTIVE

Whether knee instability contributes to the increased risk of falls and fractures observed in persons with knee osteoarthritis (OA) has not been studied. We examined the association of knee buckling with the risk of falling and fall-related consequences in older adults with, or at high risk for, knee OA.

METHODS

At the 60-month visit of the Multicenter Osteoarthritis Study, men and women ages 55-84 years were asked about knee buckling in the past 3 months and whether they fell when a knee buckled. Falls and fall-related injuries in the past 12 months and balance confidence were assessed at 60 and 84 months. Multivariate logistic regression was used to assess the association of knee buckling with falls and their consequences.

RESULTS

A total of 1,842 subjects (59% women, mean ± SD age 66.9 ± 7.8 years, and body mass index 30.3 ± 5.7) were included. At 60 months 16.8% reported buckling and at 84 months 14.1% had recurrent (≥2) falls. Bucklers at 60 months had a 1.6- to 2.5-fold greater odds of recurrent falls, fear of falling, and poor balance confidence at 84 months. Those who fell when a knee buckled at baseline had a 4.5-fold, 2-fold, and 3-fold increased odds 2 years later of recurrent falls, significant fall injuries, and fall injuries that limited activity, respectively, and were 4 times more likely to have poor balance confidence.

CONCLUSION

Interventions that reduce knee buckling may help prevent falls, fall-related injuries, and adverse psychological consequences of falls in persons with knee OA.

Obesity Paradox in Recurrent Attacks of Gout in Observational Studies: Clarification and Remedy

OBJECTIVE

Obesity is strongly associated with incident gout risk, but its association with the risk of recurrent gout attacks has been null or weak, constituting an obesity paradox. We sought to demonstrate and overcome the methodologic issues associated with the obesity paradox for risk of recurrent gout attacks.

METHODS

Using the Multiple Risk Factor Intervention Trial database, we decomposed the total effect of obesity into its direct and indirect (i.e., mediated) effects using marginal structural models. We also estimated the total effect of body mass index (BMI) change from baseline among incident gout patients.

RESULTS

Of 11,816 gout-free subjects at baseline, we documented 408 incident gout cases, with 132 developing recurrent gout attacks over a 7-year followup period. The adjusted odds ratio (OR) for incident gout among obese individuals was 2.6, whereas that for recurrent gout attacks among gout patients was 0.98 (i.e., the obesity paradox). These ORs correlated well with the ORs for the indirect and direct effects of obesity on the risk of recurrent gout attacks (2.83 and 0.98, respectively). Compared with no BMI change, the OR of increasing versus decreasing >5% of baseline BMI was 0.61 and 1.60 for recurrent gout attacks, respectively (P for trend < 0.01), suggesting a dose-response association.

CONCLUSION

The obesity paradox for the risk of recurrent gout attacks is explained by the absence of the direct effect, which is often measured in conventional analyses and misinterpreted as the intended total effect of interest. In contrast, the BMI change analysis correctly estimated the intended total effect of BMI, and revealed a dose-response relationship.

Preoperative Pain and Function: Profiles of Patients Selected for Total Knee Arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is an effective treatment to relieve pain and restore function in patients with advanced knee osteoarthritis. TKA utilization is growing rapidly, and the appropriateness of current TKA use is of great interest. We examined patient-reported preoperative pain and function profiles to understand symptom severity at the time of TKA decision.

METHODS

Data were from the Function and Outcomes Research for Comparative Effectiveness in Total Joint Replacement. We included patients undergoing primary, unilateral TKAs between 2011 and 2014 for osteoarthritis and had data on the Knee Injury and Osteoarthritis Outcome Score (KOOS) pain and Short-Form 36-item Physical Component Summary (PCS) score. We compared patient profiles across groupings by symptoms: (1) little pain and high function (KOOS ≥70, PCS ≥40); (2) little pain but poor function (KOOS ≥70, PCS <40); (3) high pain but high function (KOOS <70, PCS ≥40); and (4) high pain and poor function (KOOS <70, PCS <40).

RESULTS

Of 6936 patients, 77% had high pain and poor function (group 4), 19% had high pain "or" poor function (groups 2-3), and 5% had little pain and high function before TKA (group 1). In group 1, 86% were constantly aware of their knee problem, 48% reported pain daily yet 5% experienced severe or extreme pain on stairs, and 1% pain in bed. Over half had a lot of limitations in vigorous activities. Compared with group 4, group 1 were older, less obese, more educated, and included more men and people reporting being healthy, less disabled, and happy (P < .05 for all).

CONCLUSION

Most patients undergoing TKAs had significant pain and/or poor function. Our results provide critical information given the current debate of potentially inappropriate TKA utilization in the United States.

Trajectories of functional decline in knee osteoarthritis: the Osteoarthritis Initiative

OBJECTIVE

To describe trajectories of functional decline over 84 months and study associated risk factors among adults initially without limitation who had or were at risk of knee OA.

METHODS

We used annual measures of WOMAC physical function over 84 months from the OA Initiative. We included knees with no functional limitation (i.e. WOMAC = 0) at baseline. Knee-based trajectories of functional decline from WOMAC were identified from a group-based trajectory model (PROC TRAJ).

RESULTS

We identified five trajectories from 2110 knees (1055 participants, age 61.0 ± 9.3, BMI 27.1 ± 4.4, 52% women). Half of the knees (54%) remained free of limitation over 84 months, 26% slowly declined to a WOMAC of 1.5, 9% were limitation free for the first 36 months and declined to a WOMAC of 11.3, 6% rapidly declined over the first 12 months and gradually recovered to a WOMAC of 3.3 and 5% steadily declined to a WOMAC of 13.2. Baseline radiographic disease, knee pain, obesity and depressive symptoms at baseline were associated with trajectories of worse functional decline.

CONCLUSION

Five per cent of our sample initially without limitation was on a trajectory of progressive functional decline over 84 months later. We found worse disease and health status at baseline to be associated with faster decline over time.

Association of handgrip strength with chronic diseases and multimorbidity: a cross-sectional study

The prevalence of chronic diseases has risen along with increased longevity. Co-occurrence of two or more chronic diseases in an individual (multimorbidity) is prevalent and poses a huge burden to individuals and the society. However, determinants of multimorbidity are largely unknown. Handgrip strength is a general indicator of muscle strength and linked with premature mortality. However, its role in multimorbidity has never been evaluated. To investigate the relationships between handgrip strength and multiple chronic diseases and multimorbidity, and to assess the usefulness of age and handgrip as a marker of chronic diseases and multimorbidity in a community dwelling sample of men and women, we analyzed a cross-sectional cohort with 1,145 subjects (748 men and 397 women) aged 50 years and older living in Hong Kong. Low handgrip strength was significantly associated with increased odds of having five and three chronic diseases in men and women, respectively, after controlling for age, body mass index, history of smoking, educational level, marital level and comorbidity. Multivariable-adjusted handgrip strength was significantly decreased with the number of chronic diseases in men (trend, P = 0.001), but the trend in women was marginal (trend, P = 0.06). Conversely, multivariable-adjusted age was significantly increased with the number of chronic diseases in women (trend, P = 0.033), but not in men (trend, P = 0.118). In conclusion, handgrip strength is associated with multiple chronic diseases and multimorbidity in men and women after adjustment of confounding factors. It shows a linear trend of association with the number of chronic diseases in men, but not in women. Since handgrip strength is a biomarker of multiple physiological systems, its augmentation may be a feasible strategy to improve general health and decrease likelihood of having multiple chronic diseases and hence, premature mortality.

Correlations of clinical and laboratory measures of balance in older men and women

OBJECTIVE

It is known that impaired balance is associated with falls in older adults; however, there is no accepted gold standard on how balance should be measured. Few studies have examined measures of postural sway and clinical balance concurrently in large samples of community-dwelling older adults. We examined the associations among 4 types of measures of laboratory- and clinic-based balance in a large population-based cohort of older adults.

METHODS

We evaluated balance measures in the Maintenance of Balance, Independent Living, Intellect and Zest in the Elderly Boston Study (276 men and 489 women ages 64-97 years). The measures included laboratory-based anteroposterior (AP) path length and mean sway speed, mediolateral (ML) mean sway and root mean square, and area of ellipse postural sway; the Short Physical Performance Battery (SPPB); the Berg Balance Scale; and the one-leg stand test. Spearman's rank correlation coefficients were assessed among the balance measures.

RESULTS

The area of ellipse sway was highly correlated with the ML sway measures (r = >0.91, P < 0.0001) and sway speed was highly correlated with AP sway (r = 0.97, P < 0.0001). The Berg Balance Scale was highly correlated with the SPPB (r = 0.74, P < 0.001) and the one-leg stand test (r = 0.82, P < 0.001). Correlations between the laboratory- and clinic-based balance measures were low but statistically significant (-0.29 ≤ r ≤ -0.16, P < 0.0001).

CONCLUSION

Clinic-based balance measures, and laboratory-based measures comparing area of ellipse with ML sways or sway speed with AP sway, are highly correlated. There is less correlation between the clinic- and laboratory-based measures. Since both laboratory- and clinic-based measures inform balance in older adults, but are not highly correlated with each other, future work should investigate the differences.

The occurrence of ipsilateral or contralateral foot disorders and hand dominance: the Framingham foot study

BACKGROUND

To our knowledge, hand dominance and side of foot disorders has not been described in the literature. We sought to evaluate whether hand dominance was associated with ipsilateral foot disorders in community-dwelling older men and women.

METHODS

Data were from the Framingham Foot Study (N = 2,089, examined 2002-2008). Hand preference for writing was used to classify hand dominance. Foot disorders and side of disorders were based on validated foot examination findings. Generalized linear models with generalized estimating equations were used to estimate odds ratios and 95% confidence intervals, accounting for intraperson variability.

RESULTS

Left-handed people were less likely to have foot pain or any foot disorders ipsilateral but were more likely to have hallux valgus ipsilateral to the left hand. Among right-handed people, the following statistically significant increased odds of having an ipsilateral versus contralateral foot disorder were seen: 30% for Morton's neuroma, 18% for hammer toes, 21% for lesser toe deformity, and a twofold increased odds of any foot disorder; there was a 17% decreased odds for Tailor's bunion and an 11% decreased odds for pes cavus.

CONCLUSIONS

For the 2,089 study participants, certain forefoot disorders were shown to be ipsilateral and others were contralateral to the dominant hand. Future studies should examine whether the same biological mechanism that explains ipsilateral hand and foot preference may explain ipsilateral hand dominance and forefoot disorders.

Increasing prevalence of knee pain and symptomatic knee osteoarthritis: survey and cohort data

BACKGROUND

A recent surge in knee replacements is assumed to be due to aging and increased obesity of the U.S. population.

OBJECTIVE

To assess whether age, obesity, and change in radiographic knee osteoarthritis explain the trend in knee pain and osteoarthritis.

DESIGN

Cross-sectional, using data from 6 NHANES (National Health and Nutrition Examination Survey) surveys between 1971 and 2004 and from 3 examination periods in the FOA (Framingham Osteoarthritis) Study between 1983 through 2005.

SETTING

U.S. population.

PARTICIPANTS

NHANES participants (white or African American; aged 60 to 74 years) and FOA Study participants (mostly white; aged ≥70 years) were included.

MEASUREMENTS

NHANES participants were asked about pain in or around the knee on most days. In the FOA Study, participants were asked about knee pain and had bilateral weight-bearing anteroposterior knee radiography to define radiographic knee osteoarthritis. Radiographic evidence and self-reported pain were used to define symptomatic knee osteoarthritis. The age- and age- and body mass index (BMI)-adjusted prevalences of knee pain and osteoarthritis at later examinations were compared with that of earlier examinations by using the ratio of the prevalence estimates.

RESULTS

Age- and BMI-adjusted prevalence of knee pain increased by about 65% in NHANES from 1974 to 1994 among non-Hispanic white and Mexican American men and women and among African American women. In the FOA Study, the age- and BMI-adjusted prevalence of knee pain and symptomatic knee osteoarthritis approximately doubled in women and tripled in men over 20 years. No such trend was observed in the prevalence of radiographic knee osteoarthritis in FOA Study participants. After age adjustment, additional adjustment for BMI resulted in a 10% to 25% decrease in the prevalence ratios for knee pain and symptomatic knee osteoarthritis.

LIMITATIONS

Differences in sampling of FOA Study participants over time or birth cohort effects cannot be ruled out as possible explanations of the increased reporting of knee pain. Increases in prevalence at the last interval in the FOA Study might be due to differences in cohort membership by interval.

CONCLUSION

Results suggest that the prevalence of knee pain has increased substantially over 20 years, independent of age and BMI. Obesity accounted for only part of this increase. Symptomatic knee osteoarthritis increased but radiographic knee osteoarthritis did not.

PRIMARY FUNDING SOURCE

American College of Rheumatology Research and Education Foundation and National Institutes of Health. The FOA Study was funded by the National Heart, Lung, and Blood Institute (for the parent Framingham Heart Study), National Institute on Aging, and National Institute of Arthritis and Musculoskeletal and Skin Diseases (FOA Study), National Institutes of Health.

Increasing prevalence of knee pain and symptomatic knee osteoarthritis: survey and cohort data

BACKGROUND

A recent surge in knee replacements is assumed to be due to aging and increased obesity of the U.S. population.

OBJECTIVE

To assess whether age, obesity, and change in radiographic knee osteoarthritis explain the trend in knee pain and osteoarthritis.

DESIGN

Cross-sectional, using data from 6 NHANES (National Health and Nutrition Examination Survey) surveys between 1971 and 2004 and from 3 examination periods in the FOA (Framingham Osteoarthritis) Study between 1983 through 2005.

SETTING

U.S. population.

PARTICIPANTS

NHANES participants (white or African American; aged 60 to 74 years) and FOA Study participants (mostly white; aged ≥70 years) were included.

MEASUREMENTS

NHANES participants were asked about pain in or around the knee on most days. In the FOA Study, participants were asked about knee pain and had bilateral weight-bearing anteroposterior knee radiography to define radiographic knee osteoarthritis. Radiographic evidence and self-reported pain were used to define symptomatic knee osteoarthritis. The age- and age- and body mass index (BMI)-adjusted prevalences of knee pain and osteoarthritis at later examinations were compared with that of earlier examinations by using the ratio of the prevalence estimates.

RESULTS

Age- and BMI-adjusted prevalence of knee pain increased by about 65% in NHANES from 1974 to 1994 among non-Hispanic white and Mexican American men and women and among African American women. In the FOA Study, the age- and BMI-adjusted prevalence of knee pain and symptomatic knee osteoarthritis approximately doubled in women and tripled in men over 20 years. No such trend was observed in the prevalence of radiographic knee osteoarthritis in FOA Study participants. After age adjustment, additional adjustment for BMI resulted in a 10% to 25% decrease in the prevalence ratios for knee pain and symptomatic knee osteoarthritis.

LIMITATIONS

Differences in sampling of FOA Study participants over time or birth cohort effects cannot be ruled out as possible explanations of the increased reporting of knee pain. Increases in prevalence at the last interval in the FOA Study might be due to differences in cohort membership by interval.

CONCLUSION

Results suggest that the prevalence of knee pain has increased substantially over 20 years, independent of age and BMI. Obesity accounted for only part of this increase. Symptomatic knee osteoarthritis increased but radiographic knee osteoarthritis did not.

PRIMARY FUNDING SOURCE

American College of Rheumatology Research and Education Foundation and National Institutes of Health. The FOA Study was funded by the National Heart, Lung, and Blood Institute (for the parent Framingham Heart Study), National Institute on Aging, and National Institute of Arthritis and Musculoskeletal and Skin Diseases (FOA Study), National Institutes of Health.

Indoor and outdoor falls in older adults are different: the maintenance of balance, independent living, intellect, and Zest in the Elderly of Boston Study

OBJECTIVES

To identify risk factors for indoor and outdoor falls.

DESIGN

Prospective cohort study.

SETTING

The MOBILIZE Boston Study, a study of falls etiology in community-dwelling older individuals.

PARTICIPANTS

Seven hundred sixty-five women and men, mainly aged 70 and older, from randomly sampled households in the Boston, Massachusetts, area.

MEASUREMENTS

Baseline data were collected by questionnaire and comprehensive clinic examination. During follow-up, participants recorded falls on daily calendars. The location and circumstances of each fall were asked during telephone interviews.

RESULTS

Five hundred ninety-eight indoor and 524 outdoor falls were reported over a median follow-up of 21.7 months. Risk factors for indoor falls included older age, being female, and various indicators of poor health. Risk factors for outdoor falls included younger age, being male, and being relatively physically active and healthy. For instance, the age- and sex-adjusted rate ratio for having much difficulty or inability to perform activities of daily living relative to no difficulty was 2.57 (95% confidence interval (CI) = 1.69-3.90) for indoor falls but 0.27 (95% CI = 0.13-0.56) for outdoor falls. The rate ratio for gait speed of less than 0.68 m/s relative to a speed of greater than 1.33 m/s was 1.48 (95% CI = 0.81-2.68) for indoor falls but 0.27 (95% CI = 0.15-0.50) for outdoor falls.

CONCLUSION

Risk factors for indoor and outdoor falls differ. Combining these falls, as is done in many studies, masks important information. Prevention recommendations for noninstitutionalized older people would probably be more effective if targeted differently for frail, inactive older people at high risk for indoor falls and relatively active, healthy people at high risk for outdoor falls.

Footwear and Falls in the Home Among Older Individuals in the MOBILIZE Boston Study

BACKGROUND: Whether certain types of footwear, such as slippers, socks without shoes, and going barefoot, increase the risk for falls among the elderly is uncertain. Our purpose was to examine the relationship between footwear and falls within the home in MOBILIZE Boston, a prospective cohort study of falls etiology among non-institutionalized women and men, mainly aged 70 years and older, from the Boston MA, USA area. METHODS: The 765 participants were from households randomly selected from town lists. They were followed for a median of 27.5 months. At baseline, participants were administered a questionnaire that included questions on footwear usually worn, and were given a comprehensive examination that included measurement of many risk factors for falls. During follow-up participants were asked to record each day whether they had fallen; those reporting falls were asked about their footwear when they fell. RESULTS: At the time of in-home falls, 51.9% of people were barefoot, wearing socks without shoes, or wearing slippers; 10.1% of people reported that their usual footwear was one of these types. Among those who fell in their own home, the adjusted odds ratio for a serious injury among those who were shoeless or wearing slippers compared to those who were wearing other shoes at the time of the fall was 2.27 (95% confidence interval 1.21-4.24). CONCLUSIONS: It may be advisable for older individuals to wear shoes in their home whenever possible to minimize the risk of falling. Further research is needed to identify optimal footwear for falls prevention.

Foot pain: is current or past shoewear a factor?

OBJECTIVE

Foot pain is common, yet few studies have examined the condition in relationship to shoewear. In this cross-sectional study of men and women from the population-based Framingham Study, the association between foot pain and type of shoewear was examined.

METHODS

Data were collected on 3,378 members of the Framingham Study who completed the foot examination in 2002-2008. Foot pain (both generalized and at specific locations) was measured by the response to the question "On most days, do you have pain, aching or stiffness in either foot?" Shoewear was recorded for the present time and 5 past age categories, by the subject's choice of the appropriate shoe from a list. The responses were categorized into 3 groups (good, average, or poor shoes). Sex-specific multivariate logistic regression models were used to examine the effect of shoewear (average shoes were the referent group) on generalized and location-specific foot pain, adjusting for age and weight.

RESULTS

In women, compared with average shoes, those who wore good shoes in the past were 67% less likely to report hindfoot pain (P = 0.02), after adjusting for age and weight. In men, there was no association between foot pain, at any location, and shoewear, possibly due to the fact that <2% wore bad shoe types, making it difficult to see any relationship.

CONCLUSION

Even after taking age and weight into account, past shoewear use in women remained associated with hindfoot pain. Future studies should address specific support and structural features of shoewear.

Transfers among women intending a birth center delivery in the San Diego birth center study

Using data from the San Diego Birth Center Study that enrolled underserved women between 1994 and 1996, we examined demographic, sociobehavioral, and medical predictors of hospital transfer in a group of women who intended to deliver at a freestanding birth center. Of the 1808 women, 34.6% transferred to the hospital antenatally and 19.6% transferred during labor, while 45.7% delivered at the birth center. Compared with multiparous women who had never had a cesarean and never had a previous hospital delivery, nulliparous women were 2.0 times more likely (95% confidence interval [CI], 1.4-2.7), multiparous women with a previous cesarean were 2.6 times more likely (95% CI, 1.7-3.8), and women without a previous cesarean but who had a previous hospital delivery were 2.1 times more likely (95% CI, 1.5-3.0) to transfer after adjusting for other predictors of transfer. Nulliparity, cesarean history and having a previous hospital delivery were among the strongest predictors of a hospital transfer even after adjusting for demographic, sociobehavioral, and other medical conditions. Understanding predictors of transfer may assist practitioners, patients, and policy makers in considering the appropriateness of individuals for birth center delivery or to target further education to reduce nonmedical transfers.