High triglycerides and cholesterol are problems in dogs, too
If you’re an adult of a certain age, chances are you’ve had your blood triglyceride and cholesterol levels checked. High blood cholesterol and triglyceride levels are associated with a number of diseases in people, such as heart disease and stroke. Until recently, we didn’t worry much about high levels of these lipids in dogs. However, many veterinary scientists are re-evaluating the significance of triglyceride and cholesterol levels, and their relationship to diseases in dogs.
Triglycerides and cholesterol are forms of lipids, or fats, which circulate in the blood stream. After a meal, both triglycerides and cholesterol increase, then return to baseline levels in seven to 12 hours. It is important to measure blood lipid levels after a 12- to 15-hour fast, to avoid confusing normal post-meal increases with problematic hyperlipidemia. A diagnosis of hyperlipidemia is made when triglycerides or cholesterol remain elevated after a sufficient fast.
Hyperlipidemia is divided into two general categories: primary and secondary. Primary hyperlipidemia has no underlying cause and usually is inherited. Several dog breeds are predisposed to primary hyperlipidemia, with miniature schnauzers being the most common breed affected. Golden retrievers are not a breed usually associated with primary hyperlipidemia.
Secondary hyperlipidemia is the more common form of hyperlipidemia and is not breed specific. This form of hyperlipidemia is associated with many diseases, such as diabetes, hypothyroidism, and obesity. When hyperlipidemia is noted on a blood panel, it is important to look for the many secondary causes of increased triglycerides and cholesterol before making a diagnosis of primary hyperlipidemia. It also is important to confirm that the blood sample was taken after an adequate fast.
The treatment of hyperlipidemia depends on the underlying cause. Secondary hyperlipidemia usually resolves once the underlying disease is treated. In cases of primary hyperlipidemia, or in cases of secondary hyperlipidemias that don’t resolve after addressing the underlying condition, additional treatment is necessary. Diet change remains the cornerstone of treatment. Feeding a low fat, higher fiber diet can resolve many cases of hyperlipidemia. In cases where diet alone isn’t sufficient to resolve hyperlipidemia, medication is used to help lower triglyceride and cholesterol levels.
Many of the same drugs used to lower cholesterol and triglycerides in people can be used in dogs, including niacin, gemfibrozil (Lopid) and omega-3 fatty acids. The statin family of drugs has been sporadically used in dogs with high cholesterol, but anecdotal reports of serious side effects have limited its use in veterinary medicine.
Most routine veterinary blood panels commonly measure cholesterol and triglyceride levels. In the Golden Retriever Lifetime Study, 3 percent of dogs had triglyceride levels outside the normal range at baseline, and approximately 14 percent of dogs had cholesterol that fell outside normal range, with both low and high values noted. These results are a good reminder about the importance of a strict 12-hour fast prior to study blood draw. Although it is challenging to be firm about withholding food from dogs looking expectantly at their food dish, an inadequate fast can complicate interpretation of blood results, leading to additional fasting in order to obtain a truly accurate blood sample.
Many of the diseases that cause hyperlipidemia are associated with middle-aged and older dogs. As the Golden Retriever Lifetime Study dogs age, their blood panels likely will show more dogs with increased cholesterol and triglycerides. Monitoring the normal changes in lipid levels in a defined cohort will provide unique information on how lipid levels change as dogs age, and how those changes may impact or reflect health.