At the end of the lecture, I asked the presenter if he had seen a recent report on seasonal variations in cholesterol, and if so, would he start factoring that into his management strategies.
He replied that he was already taking seasonal variation into account, because he wrote the report I was citing. I love it when that happens.
The skinny on his data: total cholesterol is, on average, 4 points higher in men, 5-6 in women, in winter. There's greater variation in hypercholesterolemic patients, though. This variation is largely due to seasonal changes in plasma volume (even as we lose weight in the winter, we retain more water in the blood).
So, if a doctor starts a patient on cholesterol-lowering regimen in January, and checks the lipid panel again at a 6 month follow-up, the successful decline could be artificially inflated. Likewise, one shouldn't get discouraged by what appears as meager progress from June to December.
Note: Hat tip to Medpundit with bringing the cholesterol variation report to my attention originally, and I should add that any transcription or interpretation errors in this post are my own, and not the fault of today's lecturer.