Cholesterol levels 20% higher after Christmas than in summer

The extra butter, cream and fats that go into Christmas cooking may raise people’s risk of elevated cholesterol by up to six times immediately following the holidays, suggesting diagnoses of hypercholesterolemia should wait until later in the year, according to a Danish study published in Atherosclerosis.

For Danes, Christmastime is traditionally accompanied by “hygge”—a term that loosely translates to “spending cozy time together,” Signe Vedel-Krogh, MD, and coauthors wrote in the journal. As in many other cultures, “hygge” comes with family, drinks and plenty of roasted meats, rich sauces and sugar-glazed delicacies.

“A long-term high-fat diet has been associated with higher total and low-density lipoprotein (LDL) cholesterol compared with a low-fat diet, at least in overweight and obese individuals,” Vedel-Krogh and colleagues wrote, noting the holidays are also spent mainly indoors, sedentary. “Thus, a month of ‘hygge’ accompanied by a Danish Christmas diet could potentially influence patients’ chance of a hypercholesterolemia diagnosis if cholesterol levels are determined immediately following the Christmas holidays.”

The authors drew data from 25,764 adults enrolled in the Copenhagen General Population Study, which tracks cholesterol levels throughout the calendar year. The team defined hypercholesterolemia as total cholesterol greater than 5 mmol/L or LDL-cholesterol greater than 3 mmol/L.

Compared to exam results from May and June, individuals who were examined in December and January had 15 percent higher total cholesterol levels, according to analysis. LDL-cholesterol levels were 20 percent higher during the holidays.

“We found that levels of total and LDL-cholesterol were higher during and immediately following Christmas,” Vedel-Krogh et al. said. “Additionally, the fraction of individuals with hypercholesterolemia was higher during Christmas and immediately after the holidays compared to the rest of the year, with a 6 times higher risk of hypercholesterolemia in individuals attending the study in the first week of January compared to individuals attending the study during the rest of the year. These are novel findings.”

During the first week of January, 77 percent of study participants recorded LDL-cholesterol levels of greater than 3 mmol/L, and 89 percent had total cholesterol levels above 5 mmol/L.

“Mechanistically, the observed variations in total and LDL-cholesterol could be explained by intake of the high-fat diet traditionally consumed during Danish Christmas season, spanning all of December until and including New Year’s Eve,” the authors wrote. “Furthermore, the corresponding lower levels observed in late winter could be partly due to the tendency to make New Year’s resolutions and briefly engage in eating healthier following the Christmas holidays.”

Vedel-Krogh et al. said because of the nature of the data, it’s likely not a good idea to rely on cholesterol readings from early January for a diagnosis of hypercholesterolemia. Patients perceived to be at risk for high cholesterol should be tested later in the year, “and certainly prior to initiation of cholesterol-lowering treatment.”

The team’s study follows December study that found heart attack rates in Sweden spike on Christmas Eve, Christmas Day and New Year’s Eve—likely the result of increased stress and, as with the Danes, an excess of fatty foods and alcohol.