A pinboard by
Ahmed Elmaraezy

MBBCh candidate, Faculty of Medicine, Al-Azhar University, Cairo, Egypt


Vaccination during the early years of life can be protective against childhood leukemia.

Background Leukemia is the most commonly diagnosed childhood cancer. Although the survival rate for leukemia has steadily improved, its etiology is still largely unknown. Various hypotheses have been proposed to explain the etiology of childhood leukemia. There is a growing evidence that supports a role for infection in the etiology of acute lymphocytic leukemia (ALL) and hence the effects of vaccination have been extensively investigated. However, the literature shows contradictory results regarding this issue.

Objectives The objective of this systematic review and meta-analysis is to determine the association between the early vaccination and the risk of childhood leukemia.

Methods We searched nine scientific publication databases; PubMed, Scopus, Google Scholar, Web of Science, WHO Global Health Library, POPLINE, Virtual Health Library, New York Academy of Medicine (NYAM) and System for Information on Grey Literature in Europe (SIGLE). Studies were included if they reported a relationship between the childhood vaccination and the risk of leukemia, and were judged to be of good quality after rigorous assessment.

Results Nine studies with 12 data sets were identified. Meta-analysis of published results showed a significant protective association between Bacille Calmette–Guerin (BCG) vaccination and risk of childhood leukemia (summary odds ratio [OR] 0.73; 95% confidence interval [CI] 0.57-0.94). There was little or no evidence of any association with Triple vaccine, hepatitis B vaccine (HBV), Polio, Measles, Rubella, or Measles, Mumps, and Rubella (MMR).

Conclusion BCG vaccinated children appear to have a lower risk of leukemia. This finding needs to be replicated, and its impact should be interpreted in the context of changing vaccination policy.


Chemotherapy-only treatment effects on long-term neurocognitive functioning in childhood ALL survivors: a review and meta-analysis.

Abstract: Therapy for childhood acute lymphoblastic leukemia (ALL) is associated with 5-year survival rates of ∼90% even after largely eliminating cranial radiation. This meta-analysis assesses the long-term neurocognitive functioning after chemotherapy-only regimens among survivors of childhood ALL. We conducted a systematic review to identify studies that evaluated long-term neurocognitive functioning following treatment of ALL by searching MEDLINE/PubMed, Database of Abstracts of Reviews of Effects, and secondary sources. Studies were included if ALL survivors were in continuous first remission, did not receive any radiation, were at least ≥2 years off therapy or ≥5 years since diagnosis, and were compared with a healthy control group. Weighted mean differences with 95% confidence intervals (CIs) were calculated. Ten nonexperimental studies met all eligibility criteria and included 509 patients and 555 controls. Meta-analysis demonstrated statistically significant moderate impairment across multiple neurocognitive domains evaluated, with intelligence most affected. Significant differences in standard deviation (SD) scores were found for Full Scale intelligence quotient (IQ) (-0.52 SD; 95% CI, -0.68 to -0.37), Verbal IQ (-0.54 SD; 95% CI, -0.69 to -0.40), and Performance IQ (-0.41 SD; 95% CI, -0.56 to -0.27); these SD scores correspond to changes in IQ of 6 to 8 points. Working memory, information processing speed, and fine motor domains were moderately, but statistically significantly, impaired. Meta-analysis of ALL survivors treated without cranial radiation demonstrated significant impairment in IQ and other neurocognitive domains. Patients and their families should be informed about these potential negative effects to encourage surveillance and educational planning. Both preventive and intervention strategies are needed.

Pub.: 07 Jun '15, Pinned: 29 Jul '17

Obesity and the receipt of influenza and pneumococcal vaccination: a systematic review and meta-analysis.

Abstract: Obesity is a risk factor for inadequate receipt of recommended preventive care services. The objective of this study was to assess the relationship between increasing body mass index and receipt of influenza and pneumococcal vaccinations. A systematic review of the PubMed, Embase, and Web of Science databases was conducted from January 1966 to May 2015 for cohort and cross-sectional studies that assessed the relationship between body mass index and the receipt of vaccinations for influenza and pneumococcus. Separate meta-analyses by obesity classification were performed using a random effects model.Six cross-sectional and three cohort studies were included. Average vaccine uptake was 50.4 % for influenza vaccination and 34.6 % for pneumococcal vaccination. Compared to normal weight patients, combined odds ratio (95 % confidence interval) for influenza vaccination was 1.11 (95 % CI 0.97-1.25) for obese (≥30 kg/m(2)) patients. When the outcome was reported by obesity class, combined odds ratios of influenza vaccination were 1.13 (95 % CI 1.02-1.24) for Class I (30-34.9 kg/m(2)) obesity, 1.21 (95 % CI 1.05-1.37) for Class II obesity (35-39.9 kg/m(2)), and 1.19 (95 % CI 0.95-1.42) for Class III obesity (≥40 kg/m(2)) patients. Compared to normal weight patients, combined odds ratio of pneumococcal vaccination were 1.20 (95 % CI 1.13-1.27) for obese patients. When the outcome was reported by obesity class, combined odds ratios were 1.08 (95 % CI 1.04-1.13) for Class I obesity patients, 1.13 (95 % CI 1.10-1.16) for Class II obesity patients, and 1.26 (95 % CI 1.15-1.38) for Class III obesity patients for pneumococcal vaccination.Combined findings from the current literature suggest that adults with obesity are more likely than non-obese peers to receive vaccination for influenza and pneumococcus. However, suboptimal vaccination coverage was observed across all body sizes, so future interventions should focus on improving vaccination rates for all adults.

Pub.: 21 May '16, Pinned: 29 Jul '17

Influenza and Pneumococcal Vaccination in Hematological Malignancies: a Systematic Review of Efficacy, Effectiveness, and Safety.

Abstract: The risk of getting influenza and pneumococcal disease is higher in cancer patients, and serum antibody levels tend to be lower in patients with hematological malignancy.To assess flu and pneumococcal vaccinations efficacy, effectiveness, and safety in onco-hematological patients.Two systematic reviews and possible meta-analysis were conducted to summarize the results of all primary study in the scientific literature about the flu and pneumococcal vaccine in onco-hematological patients. Literature searches were performed using Pub-Med and Scopus databases. StatsDirect 2.8.0 was used for the analysis.22 and 26 studies were collected respectively for flu and pneumococcal vaccinations. Protection rate of booster dose was 30% (95% CI=6-62%) for H1N1. Pooled prevalence protection rate of H3N2 and B was available for meta-analysis only for first dose, 42.6% (95% CI=23.2 - 63.3 %) and 39.6 % (95% CI=26%-54.1%) for H3N2 and B, respectively. Response rate of booster dose resulted 35% (95% CI=19.7-51.2%) for H1N1, 23% (95% CI=16.6-31.5%) for H3N2, 29% (95% CI=21.3-37%) for B.Despite the low rate of response, flu, and pneumococcal vaccines are worthwhile for patients with hematological malignancies. Patients undergoing chemotherapy in particular rituximab, splenectomy, transplant recipient had lower and impaired response. No serious adverse events were reported for both vaccines.

Pub.: 21 Sep '16, Pinned: 29 Jul '17

Association of maternal and index child's diet with subsequent leukemia risk: A systematic review and meta analysis.

Abstract: Exploring the effect of maternal and/or childhood diet on offspring leukemogenesis is challenging, given differences in food group categories, their potentially variable impact depending on time window of exposure and the multiple leukemia subtypes. We opted to quantitatively synthesize published data on the association of maternal/child diet with leukemia risk.Medline was searched until June 30th, 2016 for eligible articles on the association of childhood leukemia with consumption of (i) food groups, excluding alcoholic and non-alcoholic beverages, and (ii) specific dietary supplements before/during index pregnancy and childhood.Eighteen studies of case-control design (N=11,720 cases/18,721 controls) were included, of which nine assessed maternal dietary components, five index child's and four both, mainly focusing on acute lymphoblastic leukemia (ALL). Statistically significant inverse estimates for ALL were found (2 studies, 413 cases, 490 controls) for fruit (OR: 0.81, 95% CI: 0.67, 0.99); vegetables (OR: 0.51, 95% CI: 0.28, 0.94); legumes (OR: 0.76, 95% CI: 0.62, 0.94); fish (OR: 0.27, 95% CI: 0.14, 0.53, among the 0-4year old; 2 studies 215 cases, 215 controls); preconception folic acid supplementation (OR: 0.69, 95%CI: 0.50-0.95; published meta analysis plus 2 studies, 3511 cases, 6816 controls); and use of vitamins during pregnancy (OR: 0.81, 95%CI: 0.74-0.88; published meta analysis plus one study, 5967 cases, 8876 controls). The associations (2 studies) of the remaining food groups and maternal dietary supplements consumption during pregnancy as well as of childhood diet and supplements intake (2-4 studies) were non significant.Maternal consumption of specific food groups comprising"healthy" items of the Mediterranean diet, preconception use of folic acid and intake of vitamins during pregnancy were associated with decreased ALL risk. Further research is needed, however preferably with homogeneous dietary information and data on immunophenotypic/cytogenetic subtypes to also explore the interaction of specific macro- and micronutrients intake with gene polymorphisms.

Pub.: 29 Jan '17, Pinned: 29 Jul '17

Parental alcohol consumption and risk of leukemia in the offspring: a systematic review and meta-analysis.

Abstract: Parental alcohol consumption before and during pregnancy has been linked to adverse outcomes in the offspring including leukemogenesis. We, therefore, aimed to systematically assess and quantitatively synthesize published data on the association of paternal consumption during preconception and maternal consumption during pregnancy with leukemia risk in childhood (0-14 years). Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we searched PubMed (until February 2016) and the reference lists of the relevant studies. Observational studies examining the association between parental alcohol consumption and childhood leukemia were considered eligible. Data extracted from 39 case-control studies (over 16 000 leukemia cases and 30 000 controls) were pooled and summary-effect estimates were calculated. Subgroup analyses were carried out by main acute leukemia type [lymphoblastic or myeloid), cytogenetics/genetic polymorphisms, and specific alcohol beverages. We found a statistically significant dose-response association of any level of maternal alcohol consumption compared with nondrinking during pregnancy exclusively with acute myeloid leukemia (AML) [odds ratio (OR)moderate consumption: 1.64, 95% confidence intervals (CIs): 1.23-2.17 and ORhigh consumption: 2.36, 95% CI: 1.60-3.49]. In contrast, no association of paternal preconception consumption with any leukemia type was noted. In beverage-specific analyses, only a positive association of maternal wine drinking with childhood AML was found, which was more pronounced in analyses including only studies on infant leukemia (ORwine: 2.12, 95% CI: 1.16-3.90). The largest ever meta-analysis shows a sizeable, statistically significant dose-response association of maternal alcohol consumption during index pregnancy with AML risk. Future research exploring the role of genetic polymorphisms is anticipated to shed light on the underlying pathophysiology.

Pub.: 06 Apr '17, Pinned: 29 Jul '17

Vaccinations and Risk of Systemic Lupus Erythematosus and Rheumatoid Arthritis: A Systematic Review and Meta-analysis.

Abstract: In the past several years, more and more studies proposed some concerns on the possibly increased risk of autoimmune diseases in individuals receiving vaccinations, but published studies on the associations of vaccinations with risks of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) reported conflicting findings. A systematic review and meta-analysis was carried out to comprehensively evaluate the relationship between vaccinations and risk of SLE and RA.Pubmed, Web of Science and Embase were searched for observational studies assessing the associations of vaccinations with risks of RA and SLE. Two authors independently extracted data from those eligible studies. The quality of eligible studies was assessed by using the Newcastle-Ottawa Scale (NOS). The pooled relative risk (RR) with 95% confidence intervals (CI) was used to measure the risk of RA and SLE associated with vaccinations, and was calculated through random-effect meta-analysis.Sixteen observational studies were finally considered eligible, including 12 studies on the association between vaccinations and SLE risk and 13 studies on the association between vaccinations and RA risk. The pooled findings suggested that vaccinations significantly increased risk of SLE (RR=1.50; 95%CI 1.05-2.12, P=0.02). In addition, there was an obvious association between vaccinations and increased risk of RA (RR=1.32; 95%CI 1.09-1.60, P=0.004). Meta-analysis of studies reporting outcomes of short vaccinated time also suggested that vaccinations could significantly increase risk of SLE (RR=1.93; 95%CI 1.07-3.48, P=0.028) and RA (RR=1.48; 95%CI 1.08-2.03, P=0.015). Sensitivity analyses in studies with low risk of bias also found obvious associations of vaccinations with increased risk of RA and SLE.This study suggests that vaccinations are related to increased risks of SLE and RA. More and larger observational studies are needed to further verify the findings above and to assess the associations of vaccinations with other rheumatic diseases.

Pub.: 10 May '17, Pinned: 29 Jul '17