The “Women’s Health Initiative” is a long-term health study that began in 1993 with 161,808 women aged 50-79; its objective was to study the relationships between health (medical history), lifestyle (questionnaires), and risk factors, over time, with respect specific disorders. At the end of the initial study period (1993-2005), the follow-up of all women who consented continued, and this has enabled to perform many studies with their data (in subgroups of participants, varying the number of women included depending on the characteristics required for the purpose of the study).
One of them has analysed the relation between the level of EPA plus DHA in red blood cells (that has been demonstrated to be a valid measure of omega-3 fatty acids intake) and longevity. The interest in studying this relationship came up from the observation of the fact that the Japanese have very high omega-3 fatty acid levels (very high intake of them), and are among the longest-lived populations of the world. Thus, relations between red blood cell fatty acids and all-cause mortality were studied in 6,501 postmenopausal women aged 65 to 80 (whose participation began in 1996).
After a median of almost 15 years of follow-up, 1,851 women (28.5%) had died: red blood cells levels of EPA and DHA were significantly lower in those who died during follow-up than those who did not (in other words, levels of EPA plus DHA were significantly higher in the survivors). In terms of probability, it was observed an 8% reduction in risk of mortality associated with higher EPA plus DHA levels.
These findings support the beneficial relationship between red blood cell omega-3 fatty acids content (this is to say, their intake) and health outcomes.