The necessity of an observational study on the interactions between allergic history and citrus fruit intake for the prevention of pancreatic cancer

Citation Discovery Tools for Conducting Adaptive Meta-analyses to Update Systematic Reviews

OBJECTIVES

The systematic review (SR) is a research methodology that aims to synthesize related evidence. Updating previously conducted SRs is necessary when new evidence has been produced, but no consensus has yet emerged on the appropriate update methodology. The authors have developed a new SR update method called 'adaptive meta-analysis' (AMA) using the 'cited by', 'similar articles', and 'related articles' citation discovery tools in the PubMed and Scopus databases. This study evaluates the usefulness of these citation discovery tools for updating SRs.

METHODS

Lists were constructed by applying the citation discovery tools in the two databases to the articles analyzed by a published SR. The degree of overlap between the lists and distribution of excluded results were evaluated.

RESULTS

The articles ultimately selected for the SR update meta-analysis were found in the lists obtained from the 'cited by' and 'similar' tools in PubMed. Most of the selected articles appeared in both the 'cited by' lists in Scopus and PubMed. The Scopus 'related' tool did not identify the appropriate articles.

CONCLUSIONS

The AMA, which involves using both citation discovery tools in PubMed, and optionally, the 'related' tool in Scopus, was found to be useful for updating an SR.

Human papillomavirus infection and risk of lung cancer in never-smokers and women: an 'adaptive' meta-analysis

OBJECTIVES:

The incidence of lung cancer in Koreans is increasing in women and in both men and women with a never-smoking history. Human papillomavirus (HPV) infection has been suggested as a modifiable risk factor of lung cancer in never-smokers and women (LCNSW). This systematic review (SR) aimed to evaluate an association between HPV infection and lung cancer risk in LCNSW.

METHODS:

Based on a prior SR and some expert reviews, we identified refereed, cited, or related articles using the PubMed and Scopus databases. All case-control studies that reported the odds ratio of HPV infection in LCNSW were selected. An estimate of the summary odds ratio (SOR) with 95% confidence intervals (CI) was calculated.

RESULTS:

A total of four case-control studies were included. The fixed-effect model was applied because of homogeneity (I-squared=0.0%). The SORs in women and in never-smokers were 5.32 (95% CI, 1.75 to 16.17) and 4.78 (2.25 to 10.15) respectively.

CONCLUSIONS:

These results showed a significant effect of HPV infection in LCNSW. It is evident that developing a preventive plan against LCNSW may be necessary.

Hormonal Replacement Therapy and the Risk of Lung Cancer in Women: An Adaptive Meta-analysis of Cohort Studies

Objectives:

Approximately 10% to 15% of lung cancer cases occur in never-smokers. Hormonal factors have been suggested to lead to an elevated risk of lung cancer in women. This systematic review (SR) aimed to investigate the association between hormonal replacement therapy (HRT) and the risk of lung cancer in women using cohort studies.

Methods:

We first obtained previous SR articles on this topic. Based on these studies we made a list of refereed, cited, and related articles using the PubMed and Scopus databases. All cohort studies that evaluated the relative risk of HRT exposure on lung cancer occurrence in women were selected. Estimate of summary effect size (sES) with 95% confidence intervals (CIs) were calculated.

Results:

A total of 14 cohort studies were finally selected. A random effect model was applied due to heterogeneity (I-squared, 64.3%). The sES of the 14 articles evaluating the impact of HRT exposure on lung cancer occurrence in women indicated no statistically significant increase in lung cancer risk (sES, 0.99; 95% CI, 0.90 to 1.09).

Conclusions:

These results showed that HRT history had no effect on the risk of lung cancer in women, even though the sES of case-control studies described in previous SR articles indicated that HRT had a protective effect against lung cancer. It is necessary to conduct a pooled analysis of cohort studies.

Hormone Replacement Therapy and Risk of Breast Cancer in Korean Women: A Quantitative Systematic Review

Objectives:

The epidemiological characteristics of breast cancer incidence by age group in Korean women are unique. This systematic review aimed to investigate the association between hormone replacement therapy (HRT) and breast cancer risk in Korean women.

Methods:

We searched electronic databases such as KoreaMed, KMbase, KISS, and RISS4U as well as PubMed for publications on Korean breast cancer patients. We also conducted manual searching based on references and citations in potential papers. All of the analytically epidemiologic studies that obtained individual data on HRT exposure and breast cancer occurrence in Korean women were selected. We restricted the inclusion of case-control studies to those that included age-matched controls. Estimates of summary odds ratio (SOR) with 95% confidence intervals (CIs) were calculated using random effect models.

Results:

One cohort and five case-control studies were finally selected. Based on the heterogeneity that existed among the six studies (I-squared=70.2%), a random effect model was applied. The summary effect size of HRT history from the six articles indicated no statistical significance in breast cancer risk (SOR, 0.983; 95% CI, 0.620 to 1.556).

Conclusions:

These facts support no significant effect of HRT history in the risk of breast cancer in Korean women. It is necessary to conduct a pooled analysis.