Is cancer or heart problems caused by too much hard work, too much anxiety, and too much depression or social isolation?

I heard a woman is half as less likely to die of breast cancer if she gives birth to a child, so I think breast cancer might be exacerbated by loneliness, social isolation, or a feeling of disconnection with the world around her.

I met a stranger who told me he got a heart attack when he found out his fiancé cheated on him, and he spent a week in the hospital getting medical treatment, so I have proof internal pain can lead to heart problems.

Is cancer or heart problems caused by too much hard work, too much anxiety, and too much depression or social isolation?
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