The phrase "a substantial age difference" is correct and usable in written English.
It can be used when discussing the difference in age between two individuals, often in contexts related to relationships or demographics.
Example: "Their relationship raised eyebrows due to the substantial age difference between them."
Alternatives: "a significant age gap" or "a considerable age disparity".
With so many players participating in junior leagues before attending college, the result is a substantial age difference between the hockey players and the rest of the student body.
It was significantly negatively associated with living in the Northern Province, the relationship being poor and there being a substantial age difference between partners.
There is a substantial age difference here.
We speculated that IPV might be associated with parous women having not yet provided a son, or with a substantial age difference or difference in education between wife and husband [ 15].
Because of the substantial age difference of patients with CAD and controls, we stratified the control group by age.
It is reasonable to assume that such substantial age difference would somehow influence the frequency of aneuploidy, even if our animals were not at the end of their lifespan yet.
Having said that, in the early phases, a stricter set of inclusion criteria will be followed, thus avoiding a potential problem with co-morbidities and substantial age differences, for instance.
12 Although no age interaction was demonstrated in this study, the participants displayed substantial age differences, which makes it likely that the LBP recorded has many different sources.
These results suggest that there are substantial age differences in response to HRT discontinuation.
No substantial age differences with respect to the correlations between ADHD-RS and CHIP-CE scores were found.
The baseline correlations between the CHIP-CE and ADHD-RS scores indicated a consistent, small-to-moderate negative correlation between the core symptoms of ADHD and HR-QoL in both age groups without substantial age differences.
