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Christopher, Kenneth

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Christopher

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Kenneth

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Christopher, Kenneth
Author's Publications: search.filters.isAuthorOfPublication.5a577adb-d6f5-4cbf-b75e-b68cfc4faf31

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    Vitamin D Status and Community-Acquired Pneumonia: Results from the Third National Health and Nutrition Examination Survey
    (Public Library of Science, 2013) Quraishi, Sadeq; Bittner, Edward; Christopher, Kenneth; Camargo, Carlos
    Objective: To investigate the association between serum 25-hydroxyvitamin D [25(OH)D] level and history of community-acquired pneumonia (CAP). Patients and Methods We identified 16,975 individuals (≥17 years) from the third National Health and Nutrition Examination Survey (NHANES III) with documented 25(OH)D levels. To investigate the association of 25(OH)D with history of CAP in these participants, we developed a multivariable logistic regression model, adjusting for demographic factors (age, sex, race, poverty-to-income ratio, and geographic location), clinical data (body mass index, smoking status, asthma, chronic obstructive pulmonary disease, congestive heart failure, diabetes mellitus, stroke, chronic kidney disease, neutropenia, and alcohol consumption), and season. Locally weighted scatterplot smoothing (LOWESS) was used to depict the relationship between increasing 25(OH)D levels and the cumulative frequency of CAP in the study cohort. Results: The median [interquartile range (IQR)] serum 25(OH)D level was 24 (IQR 18–32) ng/mL. 2.1% [95% confidence interval (CI): 1.9–2.3] of participants reported experiencing a CAP within one year of their participation in the national survey. After adjusting for demographic factors, clinical data, and season, 25(OH)D levels <30 ng/mL were associated with 56% higher odds of CAP [odds ratio 1.56; 95% confidence interval: 1.17–2.07] compared to levels ≥30 ng/mL. LOWESS analysis revealed a near linear relationship between vitamin D status and the cumulative frequency of CAP up to 25(OH)D levels around 30 ng/mL. Conclusion: Among 16,975 participants in NHANES III, 25(OH)D levels were inversely associated with history of CAP. Randomized controlled trials are warranted to determine the effect of optimizing vitamin D status on the risk of CAP.
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    Vitamin D deficiency contributes directly to the acute respiratory distress syndrome (ARDS)
    (BMJ Publishing Group, 2015) Dancer, Rachel C A; Parekh, Dhruv; Lax, Sian; D'Souza, Vijay; Zheng, Shengxing; Bassford, Chris R; Park, Daniel; Bartis, D G; Mahida, Rahul; Turner, Alice M; Sapey, Elizabeth; Wei, Wenbin; Naidu, Babu; Stewart, Paul M; Fraser, William D; Christopher, Kenneth; Cooper, Mark S; Gao, Fang; Sansom, David M; Martineau, Adrian R; Perkins, Gavin D; Thickett, David R
    Rationale: Vitamin D deficiency has been implicated as a pathogenic factor in sepsis and intensive therapy unit mortality but has not been assessed as a risk factor for acute respiratory distress syndrome (ARDS). Causality of these associations has never been demonstrated. Objectives: To determine if ARDS is associated with vitamin D deficiency in a clinical setting and to determine if vitamin D deficiency in experimental models of ARDS influences its severity. Methods: Human, murine and in vitro primary alveolar epithelial cell work were included in this study. Findings: Vitamin D deficiency (plasma 25(OH)D levels <50 nmol/L) was ubiquitous in patients with ARDS and present in the vast majority of patients at risk of developing ARDS following oesophagectomy. In a murine model of intratracheal lipopolysaccharide challenge, dietary-induced vitamin D deficiency resulted in exaggerated alveolar inflammation, epithelial damage and hypoxia. In vitro, vitamin D has trophic effects on primary human alveolar epithelial cells affecting >600 genes. In a clinical setting, pharmacological repletion of vitamin D prior to oesophagectomy reduced the observed changes of in vivo measurements of alveolar capillary damage seen in deficient patients. Conclusions: Vitamin D deficiency is common in people who develop ARDS. This deficiency of vitamin D appears to contribute to the development of the condition, and approaches to correct vitamin D deficiency in patients at risk of ARDS should be developed. Trial registration UKCRN ID 11994.
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    A 19-year-old at 37 weeks gestation with an acute acetylsalicylic acid overdose
    (Oxford University Press, 2011) Farid, Huma; Wojcik, Monica; Christopher, Kenneth
    Acute salicylate overdose in pregnancy is potentially fatal for both the mother and fetus and presents a unique challenge in intensive care management. While suggested thresholds exist for hemodialysis in adults with toxic salicylate ingestion, it is unclear if these thresholds remain appropriate for the gravid patient, particularly given that medications such as acetylsalicylic acid may cross the placental barrier and accumulate in the fetal bloodstream. We describe a case of a gravid patient at ∼37 weeks gestational age with a self-reported acetylsalicylic acid ingestion of 32.5 g and review prior cases of both acute and chronic salicylate ingestion in pregnancy in order to determine the clinical precedent for hemodialysis in this situation.
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    Admission vitamin D status is associated with discharge destination in critically ill surgical patients
    (Springer Paris, 2015) Brook, Karolina; Camargo, Carlos; Christopher, Kenneth; Quraishi, Sadeq
    Background: Discharge destination after critical illness is increasingly recognized as a valuable patient-centered outcome. Recently, vitamin D status has been shown to be associated with important outcomes such as length of stay (LOS) and mortality in intensive care unit (ICU) patients. Our goal was to investigate whether vitamin D status on ICU admission is associated with discharge destination. Methods: We performed a retrospective analysis from an ongoing prospective cohort study of vitamin D status in critical illness. Patients were recruited from two surgical ICUs at a single teaching hospital in Boston, Massachusetts. All patients had 25-hydroxyvitamin D (25OHD) levels measured within 24 h of ICU admission. Discharge destination was dichotomized as non-home or home. Locally weighted scatterplot smoothing (LOWESS) was used to graph the relationship between 25OHD levels and discharge destination. To investigate the association between 25OHD level and discharge destination, we performed logistic regression analyses, controlling for age, sex, race, body mass index, socioeconomic status, acute physiology and chronic health evaluation II score, need for emergent vs. non-emergent surgery, vitamin D supplementation status, and hospital LOS. Results: 300 patients comprised the analytic cohort. Mean 25OHD level was 19 (standard deviation 8) ng/mL and 41 % of patients had a non-home discharge destination. LOWESS analysis demonstrated a near-inverse linear relationship between vitamin D status and non-home discharge destination to 25OHD levels around 10 ng/mL, with rapid flattening of the curve between levels of 10 and 20 ng/mL. Overall, 25OHD level at the outset of critical illness was inversely associated with non-home discharge destination (adjusted OR, 0.88; 95 % CI 0.82–0.95). When vitamin D status was dichotomized, patients with 25OHD levels <20 ng/mL had an almost 3-fold risk of a non-home discharge destination (adjusted OR, 2.74; 95 % CI 1.23–6.14) compared to patients with 25OHD levels ≥20 ng/mL. Conclusions: Our results suggest that vitamin D status may be a modifiable risk factor for non-home discharge destination in surgical ICU patients. Future randomized, controlled trials are needed to determine whether vitamin D supplementation in surgical ICU patients can improve clinical outcomes such as the successful rate of discharge to home after critical illness
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    Vitamin D Status and Acute Respiratory Infection: Cross Sectional Results from the United States National Health and Nutrition Examination Survey, 2001–2006
    (MDPI, 2015) Monlezun, Dominique J.; Bittner, Edward; Christopher, Kenneth; Camargo, Carlos; Quraishi, Sadeq
    Vitamin D is a promising, though under-explored, potential modifiable risk factor for acute respiratory infections (ARIs). We sought to investigate the association of vitamin D status with ARI in a large, nationally-representative sample of non-institutionalized individuals from the United States. We analyzed 14,108 individuals over 16 years of age in the National Health and Nutrition Survey (NHANES) 2001–2006 in this cross-sectional study. We used locally weighted scatterplot smoothing (LOWESS) to depict the relationship between increasing 25-hydroxyvitamin D (25OHD) levels and ARI. We then performed a multivariable regression analysis to investigate the association of 25OHD levels with ARI, while adjusting for known confounders. The median serum 25OHD level was 21 (IQR 15–27) ng/mL. Overall, 4.8% (95% CI: 4.5–5.2) of participants reported an ARI within 30 days before their participation in the national survey. LOWESS analysis revealed a near-linear relationship between vitamin D status and the cumulative frequency of ARI up to 25OHD levels around 30 ng/mL. After adjusting for season, demographic factors, and clinical data, 25OHD levels <30 ng/mL were associated with 58% higher odds of ARI (OR 1.58; 95% CI: 1.07–2.33) compared to levels ≥30 ng/mL. Among the 14,108 participants in NHANES 2001–2006, 25OHD levels were inversely associated with ARI. Carefully designed, randomized, controlled trials are warranted to determine the effect of optimizing vitamin D status on the risk of ARI.