The Association of Atherosclerosis and BMD in Middle-Aged Men

In this podcast, Akira Sekikawa, MD, PhD, talks about his research on the association of atherosclerosis and bone mineral density in an international cohort of middle-aged men.

Additional Resource: 

• Nakama C, Kadowaki T, Choo J, et al. Cross-sectional association of bone mineral density with coronary artery calcification in an international multi-ethnic population-based cohort of men aged 40-49: ERA JUMP study. Int J Cardiol Heart Vasc. Published online August 18, 2020. doi:10.1016/j.ijcha.2020.100618

Akira Sekikawa, MD, PhD, is an associate professor of epidemiology at the University of Pittsburgh in Pennsylvania. 

TRANSCRIPT:

Michael Potts: Hi, everyone. Welcome to another installment of Podcasts360, your go-to resource for medical news and clinical updates. I'm Michael Potts, managing digital editor at Consultant360 Specialty Network.

Previous research has indicated a possible inverse association between cardiovascular disease and atherosclerosis with osteoporosis and bone mineral density in older adults, but the relationship in middle-aged adults is less well understood.

Here with us today to speak about his research on the topic is Dr Akira Sekikawa, who is an associate professor of epidemiology at the University of Pittsburgh. Thank you for joining us today, Dr Sekikawa. Let's dive into your study. Can you tell us a little about how your study came about and how you decided on the topic?

Akira Sekikawa: As I said, I'm a cardiovascular epidemiologist in the US, but, also, I'm a physician trained in Japan. Physicians tend to focus on one organ, such as, "Oh, I am a cardiologist, pulmonologist, or neurologist," but recent advancements in science shows interconnection of these disease processes across several organs, such as cardiovascular disease is connected to the development of dementia or independent association of COPD with chronic heart disease.

This approach is called systems biology, so that the interconnection between bone mineral density and the coronary artery calcification could be interesting. This is our motive for this investigation.

Michael Potts: Previous research has indicated a link between coronary artery calcification and bone mineral density in elderly men and postmenopausal women. For your study, you chose to focus on an international group of men, aged 40 to 49 years old. Why did you choose to focus specifically on this population and not also include middle-aged, premenopausal women?

Akira Sekikawa: Thank you for that question. Actually this study's association of BMD and the coronary calcification is not the main purpose of this cohort. This cohort is established to investigate uniquely low mortality from heart attack in Japanese, in Japan. And low coronary heart disease mortality in Japanese man in Japan is very unique for three reasons. First, mortality is less than the third compared to the United States, despite a lifetime exposure to traditional risk factor that is cholesterol, blood pressure, smoking and diabetes, the worst in Japanese in Japan than the United States.

Second, mortality in Japan continues to decrease since 1960s despite the massive increase in population level total cholesterol. Third, migrant study of Japanese to the United States clearly demonstrate a dramatic rise in heart disease rate, indicating that low CHD mortality in Japan is not purely due to genetic susceptibility.

Thus, to investigate this intriguing phenomenon, we set up a cohort of 1,300 men, aged 40 to 49. Essentially, 300 native Japanese, 300 Japanese-American in Honolulu, 400 Pittsburghers, 300 white and 100 black, and 300 Koreans in South Korea, using subclinical measures of atherosclerosis. We have published probably 70+ papers from this cohort.

Overall, what we found is that the atherosclerosis level is significantly lower in native Japanese than Pittsburghers. As compared to Japanese-American and the Pittsburghers, the level of atherosclerosis are very similar or worse in Japanese-Americans. Again, indicating that low atherosclerosis in native Japanese is unlikely to be genetic susceptibility.

Also, we found the low-level inflammation in native Japanese. That is settled cohort and subanalysis of this essential data. We did investigate this association.

Michael Potts: Overall, you found that the relationship observed in older adults was also present in the population that you studied. Was this result expected, or did any of these results surprise you?

Akira Sekikawa: In a sense, we have expected these result, this association, but at the same time, it was very surprising that we observed this association in this young cohort of men, aged 40 to 49.

Michael Potts: How do you think that your findings will impact clinical practice?

Akira Sekikawa: I could say that if a physician identified coronary artery calcification in this young aged man 40 to 49, then physician need to check bone mineral density, turned out to be wonderful. However, it is unlikely that that level of bone mineral density in this age group of men would have some clinical implication. Thus, the finding is more for implication for future research on systems biology.

On the other hand, we observed this association without any interaction by racial group, so that the same inter-association exists in American, Japanese-American, Native Japanese, and Korean, which is very intriguing.

Michael Potts: What knowledge gaps still exist in this area and what should future studies focus on?

Akira Sekikawa: Several, especially inflammatory ones and other biomarkers that implicated that potential link between bone mineral density and the coronary artery calcification, that results are inconsistent or not specific. Let's say that, in our case, we adjusted for C-reactive protein but significant association remained, and the magnitude of the association was not attenuated.

CRP cannot explain this association, so that future research would investigate the potential mechanism, and that would lead to prevention of these diseases.

Michael Potts: Thank you for joining us today, Dr Sekikawa.