(Note that the category of "stress" entered public discourse at about the same time mindfulness meditation became a secularized practice in the mid-1970s. the solution emerged coincidentally with the problem.)
Actually, back in 1951 Alan Watts published The Wisdom of Insecurity: A Message for an Age of Anxiety -- a very influential and seminal work -- in which he recommended mindfulness-type methods, especially the practice of being present, as an antidote to the widespread perceived stressfulness of the times. Indeed, many writers characterized the dawn of the atomic age as a time of increasingly pervasive stressfulness, and a number of artistic productions and sociological papers took "The Age of Anxiety" as their title and theme.
Sure. The health professionals and the knowledge makers got the idea from the religious people. If you look at the early books on mindfulness by psychology people, and not just Kabat-Zinn, you'll find references to Thich Nhat Hanh & Trungpa. Think Ellen Langer here.
Even in the most sanitized & instrumentalized versions of mindfulness, it's not hard to find Buddhisty traces. It's an interesting phenomenon in that sense.
Need help getting on retreat? Want to support others in practice? Pay the Dana for Dharma forum a visit...viewtopic.php?f=114&t=13727