Author + information
- Eva J.E. Hendriks, MD∗ (, )
- Pim A. de Jong, MD, PhD,
- Joline W.J. Beulens, PhD,
- Willem P.Th.M. Mali, MD, PhD,
- Yvonne T. van der Schouw, PhD and
- David Beijerinck, MD
- ↵∗University Medical Center Utrecht, Julius Center for Health Sciences and Primary Care, Postbus 85500, Huispostnummer Stratenum 6.131, Utrecht, 3508 GA, the Netherlands
Medial arterial calcification (MAC) is currently gaining interest as a possible cause of cardiovascular disease distinct from atherosclerosis (1). Because MAC is actively regulated by processes bearing great similarities to the dynamic process of bone formation, reversibility of MAC can be expected (1). Although regression has been observed in animal models, surprisingly limited observations of MAC regression in humans are available. Currently none of the cardiovascular medications has convincingly been shown to modify arterial calcification.
Breast arterial calcification (BAC) is a type of MAC regularly observed in mammography. In breast cancer screening programs, these arteries are visualized repeatedly in a highly systematic fashion in the general population. BAC can therefore serve as a convenient model for MAC. BAC was found to be independently associated with a moderately increased cardiovascular disease risk in the general population (2). A few cases of BAC regression have been reported (3). The extent to which BAC regression occurs remains unknown.
We hypothesized that BAC regression would be present in a population of women participating in breast cancer screening. From August 1, 1998, to January 31, 1999, we screened 32,589 women by mammography within the Utrecht area in the Netherlands. After approval was obtained from the institutional review board of the University Medical Center Utrecht, the mammograms of these women were systematically investigated for BAC by 1 of 2 board-certified radiologists. If BAC was present, the index mammogram was retrospectively compared with previous mammograms, if available. Regression was defined as a decrease of arterial calcification in at least 1 segment of an artery compared with previous mammograms, as illustrated in Figure 1. To determine whether regression had occurred, both radiologists assessed the mammograms and resolved disagreements in consensus meetings.
At least 1 previous mammogram was available for 25,296 women; of these, 2,948 (11.8%) had BAC in at least 1 breast on the index mammogram. Among these 2,948 women with BAC, the BAC had regressed in 98 women (3.3%; 95% confidence interval: 2.7 to 4.0). All women with regression of BAC were sent a questionnaire regarding their medical history and cardiovascular risk factors. The 43 women (44%) who completed the questionnaire were on average 72.5 years of age with a body mass index of 25.5 kg/m2. Cardiovascular risk factors were common: 34.9% current or previous smokers, 37.2% with hypertension, 36.6% with hypercholesterolemia, 14.6% with diabetes, and 11.9% with renal disease. Although no direct comparison is possible, the characteristics of these women appear comparable to those of women with BAC described in published reports (2). Regression of BAC has been reported to occur after renal transplant, but this cannot fully explain our findings (3). The dual assessment of mammograms with BAC regression has diminished measurement error due to interrater variability; however, some measurement error may remain, due to between-mammogram variability. Most of the regression found, however, represented clear interruptions in chains of calcium that were previously not interrupted, which was easy to ascertain.
In conclusion, our study convincingly showed that MAC is a reversible process in the population. Further research into the causes of regression and possible effective therapy is warranted.
- American College of Cardiology Foundation