This is the 11478th most frequent Russian word.
долголетию
"Долголетию" means "longevity" in English.
Here 'долголетию' is used in the dative case to signify aspiration or dedication towards achieving longevity.
Иван всегда стремился к долголетию и здоровому образу жизни.
Ivan always aspired to longevity and a healthy lifestyle.
In this instance, 'долголетию' in the dative case shows the dedicatory focus of scientific research on the concept of longevity.
Научные исследования посвящены долголетию и улучшению качества жизни.
Scientific studies are dedicated to longevity and improving quality of life.
Here, 'долголетию' in the dative case is used within a congratulatory or honorary context to express good wishes for longevity.