Foot&Leg health factor (or longevity factor) F2 consists of foot angle, foot heel depth and rear legs-rear view.

F2为肢蹄因子（或者称为长寿因子），它包括蹄角度、蹄踵深度和后肢侧视。

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The Mediterranean diet is also likely to be a factor in Italian longevity.

BBC: Why do the Italians live longer than us?

However, an important factor to consider is longevity and the amount of time that this money will have to last.

FORBES: The Early Retirement Income Challenge: Longevity

Levering is helping the Society of Actuaries with its mission to improve Americans understanding of longevity and its variability, and how to factor it into their retirement planning.

FORBES: Americans Clueless About Life Expectancy, Bungling Retirement Planning