The metafor package provides functions for conducting meta-analyses in R. The package includes functions for fitting the meta-analytic fixed- and random-effects models and allows for the inclusion of moderators variables (study-level covariates) in these models. Meta-regression analyses with continuous and categorical moderators can be conducted in this way. Functions for the Mantel-Haenszel and Peto's one-step method for meta-analyses of 2 x 2 table data are also available. Finally, the package provides various plot functions (for example, for forest, funnel, and radial plots) and functions for assessing the model fit, for obtaining case diagnostics, and for tests of publication bias.

Conducting Meta-Analyses in R with the metafor Package

Considerable advances have occurred in recent years in the scientific knowledge of the benefits of breastfeeding, the mechanisms underlying these benefits, and in the clinical management of breastfeeding. This policy statement on breastfeeding replaces the 1997 policy statement of the American Academy of Pediatrics and reflects this newer knowledge and the supporting publications. The benefits of breastfeeding for the infant, the mother, and the community are summarized, and recommendations to guide the pediatrician and other health care professionals in assisting mothers in the initiation and maintenance of breastfeeding for healthy term infants and high-risk infants are presented. The policy statement delineates various ways in which pediatricians can promote, protect, and support breastfeeding not only in their individual practices but also in the hospital, medical school, community, and nation.

/pdf/breastfeeding-and-the-use-of-human-milk-2m74a0njro.pdf

Breastfeeding and the Use of Human Milk

Objective.—To estimate the incidence of serious and fatal adverse drug reactions
(ADR) in hospital patients.Data Sources.—Four electronic databases were searched from 1966 to 1996.Study Selection.—Of 153, we selected 39 prospective studies from US hospitals.Data Extraction.—Data extracted independently by 2 investigators were analyzed by a random-effects
model. To obtain the overall incidence of ADRs in hospitalized patients, we
combined the incidence of ADRs occurring while in the hospital plus the incidence
of ADRs causing admission to hospital. We excluded errors in drug administration,
noncompliance, overdose, drug abuse, therapeutic failures, and possible ADRs.
Serious ADRs were defined as those that required hospitalization, were permanently
disabling, or resulted in death.Data Synthesis.—The overall incidence of serious ADRs was 6.7% (95% confidence interval
[CI], 5.2%-8.2%) and of fatal ADRs was 0.32% (95% CI, 0.23%-0.41%) of hospitalized
patients. We estimated that in 1994 overall 2216000 (1721000-2711000) hospitalized
patients had serious ADRs and 106000 (76000-137000) had fatal ADRs, making
these reactions between the fourth and sixth leading cause of death.Conclusions.—The incidence of serious and fatal ADRs in US hospitals was found to
be extremely high. While our results must be viewed with circumspection because
of heterogeneity among studies and small biases in the samples, these data
nevertheless suggest that ADRs represent an important clinical issue.

/pdf/incidence-of-adverse-drug-reactions-in-hospitalized-patients-9vevgtzyvn.pdf

Incidence of Adverse Drug Reactions in Hospitalized Patients: A Meta-analysis of Prospective Studies

Progress in public health and community-based interventions has been hampered by the lack of a comprehensive evaluation framework appropriate to such programs. Multilevel interventions that incorporate policy, environmental, and individual components should be evaluated with measurements suited to their settings, goals, and purpose. In this commentary, the authors propose a model (termed the RE-AIM model) for evaluating public health interventions that assesses 5 dimensions: reach, efficacy, adoption, implementation, and maintenance. These dimensions occur at multiple levels (e.g., individual, clinic or organization, community) and interact to determine the public health or population-based impact of a program or policy. The authors discuss issues in evaluating each of these dimensions and combining them to determine overall public health impact. Failure to adequately evaluate programs on all 5 dimensions can lead to a waste of resources, discontinuities between stages of research, and failure to improve ...

Evaluating the public health impact of health promotion interventions: the RE-AIM framework.

To revise 1998 recommendations on childhood obesity, an Expert Committee, comprised of representatives from 15 professional organizations, appointed experienced scientists and clinicians to 3 writing groups to review the literature and recommend approaches to prevention, assessment, and treatment. Because effective strategies remain poorly defined, the writing groups used both available evidence and expert opinion to develop the recommendations. Primary care providers should universally assess children for obesity risk to improve early identification of elevated BMI, medical risks, and unhealthy eating and physical activity habits. Providers can provide obesity prevention messages for most children and suggest weight control interventions for those with excess weight. The writing groups also recommend changing office systems so that they support efforts to address the problem. BMI should be calculated and plotted at least annually, and the classification should be integrated with other information such as growth pattern, familial obesity, and medical risks to assess the child’s obesity risk. For prevention, the recommendations include both specific eating and physical activity behaviors, which are likely to promote maintenance of healthy weight, but also the use of patient-centered counseling techniques such as motivational interviewing, which helps families identify their own motivation for making change. For assessment, the recommendations include methods to screen for current medical conditions and for future risks, and methods to assess diet and physical activity behaviors. For treatment, the recommendations propose 4 stages of obesity care; the first is brief counseling that can be delivered in a health care office, and subsequent stages require more time and resources. The appropriateness of higher stages is influenced by a patient’s age and degree of excess weight. These recommendations recognize the importance of social and environmental change to reduce the obesity epidemic but also identify ways healthcare providers and health care systems can be part of broader efforts.

/pdf/expert-committee-recommendations-regarding-the-prevention-38kyxmdgpa.pdf

Expert Committee Recommendations Regarding the Prevention, Assessment, and Treatment of Child and Adolescent Overweight and Obesity: Summary Report

Objective. —To quantify the efficacy of BCG vaccine against tuberculosis (TB). Data Sources. —MEDLINE with index termsBCG vaccine, tuberculosis, andhuman. Experts from the Centers for Disease Control and Prevention and the World Health Organization, among others, provided lists of all known studies. Study Selection. —A total of 1264 articles or abstracts were reviewed for details on BCG vaccination, concurrent vaccinated and unvaccinated groups, and TB outcome; 70 articles were reviewed in depth for method of vaccine allocation used to create comparable groups, equal surveillance and follow-up for recipient and concurrent control groups, and outcome measures of TB cases and/or deaths. Fourteen prospective trials and 12 case-control studies were included in the analysis. Data Extraction. —We recorded study design, age range of study population, number of patients enrolled, efficacy of vaccine, and items to assess the potential for bias in study design and diagnosis. At least two readers independently extracted data and evaluated validity. Data Synthesis. —The relative risk (RR) or odds ratio (OR) of TB provided the measure of vaccine efficacy that we analyzed. The protective effect was then computed by 1 —RR or 1 —OR. A random-effects model estimated a weighted average RR or OR from those provided by the trials or case-control studies. In the trials, the RR of TB was 0.49 (95% confidence interval [Cl], 0.34 to 0.70) for vaccine recipients compared with nonrecipients (protective effect of 51%). In the case-control studies, the OR for TB was 0.50 (95% CI, 0.39 to 0.64), or a 50% protective effect. Seven trials reporting tuberculous deaths showed a protective effect from BCG vaccine of 71% (RR, 0.29; 95% Cl, 0.16 to 0.53), and five studies reporting on meningitis showed a protective effect from BCG vaccine of 64% (OR, 0.36; 95% Cl, 0.18 to 0.70). Geographic latitude of the study site and study validity score explained 66% of the heterogeneity among trials in a random-effects regression model. Conclusion. —On average, BCG vaccine significantly reduces the risk of TB by 50%. Protection is observed across many populations, study designs, and forms of TB. Age at vaccination did not enhance predictiveness of BCG efficacy. Protection against tuberculous death, meningitis, and disseminated disease is higher than for total TB cases, although this result may reflect reduced error in disease classification rather than greater BCG efficacy. (JAMA. 1994;271:698-702)

https://jamanetwork.com/journals/jama/articlepdf/366365/jama_271_9_038.pdf

Efficacy of BCG Vaccine in the Prevention of Tuberculosis: Meta-analysis of the Published Literature

Context: The proportion of children eating dinner with their families declines with age and has decreased over time. Few data exist concerning the nutritional effect of eating family dinner. 

Objective: To examine the associations between frequency of eating dinner with family and measures of diet quality. 

Design: Cross-sectional. 

Setting: A national convenience sample. 

Participants: There were 8677 girls and 7525 boys in the study, aged 9 to 14 years, who were children of the participants in the ongoing Nurses' Health Study II. 

Main outcome measures: We collected data from a self-administered mailed survey, including food and nutrient intakes from a validated semiquantitative food frequency questionnaire. Main outcome measures included servings per day of selected foods and food groups, daily intakes of selected macronutrients and micronutrients, and frequency of multivitamin use. 

Results: Approximately 17% of participants ate dinner with members of their family never or some days, 40% on most days, and 43% every day. More than half of the 9-year-olds ate family dinner every day, whereas only about one third of 14-year-olds did so. In age- and sex-adjusted logistic regression models, the odds ratios associated with a frequency of family dinner of most days compared with never or some days, or every day compared with most days, were as follows: for eating at least 5 servings per day of fruits and vegetables, 1.45 (95% confidence interval [CI], 1.37-1.53); for eating any fried foods away from home, 0.67 (95% CI, 0.64-0.70); and for drinking any soda, 0.73 (95% CI, 0.66-0.80). Multiple linear regression showed that an increased frequency of family dinner was also associated with substantially higher intake of several nutrients, including fiber, calcium, folate, iron, vitamins B6, B12, C, and E; lower glycemic load; and lower intake of saturated and trans fat as a percentage of energy. We observed little or no effect on intakes of whole dairy products, red meat, or snack foods. Patterns were similar for boys and girls. 

Conclusions: Eating family dinner was associated with healthful dietary intake patterns, including more fruits and vegetables, less fried food and soda, less saturated and trans fat, lower glycemic load, more fiber and micronutrients from food, and no material differences in red meat or snack foods.

Family dinner and diet quality among older children and adolescents.

ContextOverweight during adolescence predicts short- and long-term morbidity
as well as obesity in adulthood The prevalence of overweight among adolescents
is high and continues to increase Physiological and behavioral mechanisms
and preliminary epidemiologic data suggest that breastfeeding could lower
the risk of subsequent obesity in adolescenceObjectiveTo examine the extent to which overweight status among adolescents is
associated with the type of infant feeding (breast milk vs infant formula)
and duration of breastfeedingDesign, Setting, and SubjectsSurvey of 8186 girls and 7155 boys, aged 9 to 14 years, who are participants
in the Growing Up Today Study, a nationwide cohort study of diet, activity,
and growth In the fall of 1996 we mailed a questionnaire to each of the subjects,
and in the spring of 1997, we mailed a supplemental questionnaire to their
mothers, who are participants in the Nurses' Health Study IIMain Outcome MeasureOverweight status defined as body mass index exceeding the 95th percentile
for age and sex from US national dataResultsIn the first 6 months of life, 9553 subjects (62%) were only or mostly
fed breast milk, and 4744 (31%) were only or mostly fed infant formula A
total of 7186 subjects (48%) were breastfed for at least 7 months while 4613
(31%) were breastfed for 3 months or less At ages 9 to 14 years, 404 girls
(5%) and 635 boys (9%) were overweight Among subjects who had been only or
mostly fed breast milk, compared with those only or mostly fed formula, the
odds ratio (OR) for being overweight was 078 (95% confidence interval [CI],
066-091), after adjustment for age, sex, sexual maturity, energy intake,
time watching television, physical activity, mother's body mass index, and
other variables reflecting social, economic, and lifestyle factors Compared
with subjects who had been breastfed for 3 months or less, those who had been
breastfed for at least 7 months had an adjusted OR for being overweight of
080 (95% CI, 067-096) Timing of introduction of solid foods, infant formula,
or cow's milk was not related to risk of being overweightConclusionInfants who were fed breast milk more than infant formula, or who were
breastfed for longer periods, had a lower risk of being overweight during
older childhood and adolescence

https://jamanetwork.com/journals/jama/articlepdf/193840/JOC02036.pdf

Risk of overweight among adolescents who were breastfed as infants

Many meta-analyses use a random-effects model to account for heterogeneity among study results, beyond the variation associated with fixed effects. A random-effects regression approach for the synthesis of 2 x 2 tables allows the inclusion of covariates that may explain heterogeneity. A simulation study found that the random-effects regression method performs well in the context of a meta-analysis of the efficacy of a vaccine for the prevention of tuberculosis, where certain factors are thought to modify vaccine efficacy. A smoothed estimator of the within-study variances produced less bias in the estimated regression coefficients. The method provided very good power for detecting a non-zero intercept term (representing overall treatment efficacy) but low power for detecting a weak covariate in a meta-analysis of 10 studies. We illustrate the model by exploring the relationship between vaccine efficacy and one factor thought to modify efficacy. The model also applies to the meta-analysis of continuous outcomes when covariates are present.

A random-effects regression model for meta-analysis

Objective. To quantify the efficacy of vaccination of infants with bacillus Calmette-Guerin (BCG) against tuberculosis. Data sources. MEDLINE with index terms BCG vaccine, tuberculosis, and human; lists of all known studies provided by experts at the Centers for Disease Control and Prevention, the World Health Organization, and other organizations. Study selection. A total of 1264 articles and abstracts were reviewed for details on BCG vaccination, the availability of concurrent vaccinated and unvaccinated groups, and a tuberculosis outcome. Seventy articles were reviewed in depth for method of vaccine allocation used to create comparable groups, age at vaccination of study participants, comparability of surveillance and follow-up of recipient and concurrent control groups in trials, an appropriately defined control group in case-control studies, and outcome measures (tuberculosis cases and/or deaths). Five prospective trials and eleven case-control studies of vaccination during infancy were included in the present analyses. Data extraction. We recorded study design, age range of study population, number of patients enrolled, efficacy of vaccine, location of the study, and a series of items to assess the potential for bias in study design, follow-up, and diagnosis. We extracted or computed vaccine efficacy by years since vaccination wherever possible. At least two readers independently extracted data and evaluated data validity. Data synthesis. The relative risk (RR) or odds ratio (OR) for tuberculosis in vaccinated versus unvaccinated infants was the measure of vaccine efficacy analyzed. A random-effects method estimated a weighted average RR or OR from data extracted from the trials and case-control studies. The protective effect was then computed by 1 - RR or 1 - OR. Overall, the protective effect of vaccination against cases of tuberculosis was 0.74 (95% confidence interval [95% CI], 0.62 to 0.83) when estimated from four randomized controlled trials, and 0.52 (95% CI, 0.38 to 0.64) when estimated from nine case-control studies. Five trials reporting deaths from tuberculosis showed a BCG protective effect of 0.65 (95% CI, 0.12 to 0.86), five studies reporting on meningitis showed a protective effect of 0.64 (95% CI, 0.30 to 0.82), and three studies of disseminated tuberculosis showed a protective effect of 0.78 (95% CI, 0.58 to 0.88). Three case-control studies included separate results for laboratory-confirmed cases of tuberculosis. These studies documented a protective effect of 0.83 (95% CI, 0.58 to 0.93). In a random-effects regression model of the nine case-control studies, study validity score explained 15% of the heterogeneity among study-estimated protective effects, suggesting that better studies reported greater efficacy. Three trials and six case-control studies provided some age-specific information that allowed us to examine the duration of BCG efficacy. Most of this evidence suggested that BCG efficacy may persist through 10 years after infant vaccination. Conclusion. BCG vaccination of newborns and infants significantly reduces the risk of tuberculosis—by over 50%, on average. Protection has been observed across many populations, study designs, and forms of tuberculosis. Rates of protection against cases that are confirmed by laboratory tests, reflecting reduced error in disease classification and consequently more accurate estimates of BCG efficacy, are highest at 83%.

The efficacy of bacillus Calmette-Guérin vaccination of newborns and infants in the prevention of tuberculosis : meta-analyses of the published literature

Catherine S. Berkey

Papers

Efficacy of BCG Vaccine in the Prevention of Tuberculosis: Meta-analysis of the Published Literature

Family dinner and diet quality among older children and adolescents.

Risk of overweight among adolescents who were breastfed as infants

A random-effects regression model for meta-analysis

The efficacy of bacillus Calmette-Guérin vaccination of newborns and infants in the prevention of tuberculosis : meta-analyses of the published literature