  Odds ratios or p_values from individual observational studies can be combined
to examine a common cause_effect research question in meta_analysis. However,
reliability of individual studies used in meta_analysis should not be taken for
granted as claimed cause_effect associations may not reproduce. An evaluation
was undertaken on meta_analysis of base papers examining gas stove cooking,
including nitrogen dioxide, NO2, and childhood asthma and wheeze associations.
Numbers of hypotheses tested in 14 of 27 base papers, 52 percent, used in
meta_analysis of asthma and wheeze were counted. Test statistics used in the
meta_analysis, 40 odds ratios with 95 percent confidence limits, were converted
to p_values and presented in p_value plots. The median and interquartile range
of possible numbers of hypotheses tested in the 14 base papers was 15,360,
6,336_49,152. None of the 14 base papers made mention of correcting for
multiple testing, nor was any explanation offered if no multiple testing
procedure was used. Given large numbers of hypotheses available, statistics
drawn from base papers and used for meta-analysis are likely biased. Even so,
p-value plots for gas stove_current asthma and gas stove_current wheeze
associations show randomness consistent with unproven gas stove harms. The
meta-analysis fails to provide reliable evidence for public health policy
making on gas stove harms to children in North America. NO2 is not established
as a biologically plausible explanation of a causal link with childhood asthma.
Biases_multiple testing and p-hacking_cannot be ruled out as explanations for a
gas stove_current asthma association claim. Selective reporting is another bias
in published literature of gas stove_childhood respiratory health studies.
Keywords gas stove, asthma, meta-analysis, p-value plot, multiple testing,
p_hacking
