While the study follows participants over a long period, it relies on self-reported data about meal times, which may not be entirely accurate. People might not remember their exact meal times or may change their habits during the study period. The collected data may be influenced by factors like memory errors and consistency in reporting throughout the study's duration.
The study couldn't account for every possible factor that might influence both meal times and mortality, such as physical activity levels or specific dietary components. This omission could confound the results, as it is difficult to separate the influence of meal timing from the omitted factors. The relationship observed could be due to other unaccounted factors.
The older adult participants in this study may not represent the broader older adult population worldwide. The findings might not apply to older adults from other countries with different lifestyles, cultural norms, and dietary habits.
Correlation does not equal causation
The study found a correlation between later breakfast time and increased mortality, but it doesn't prove cause-and-effect. Other factors associated with later breakfast, like health issues or lifestyle differences, could be the real drivers of the higher mortality risk. The authors acknowledge this limitation and call for more research to determine a causal link.