A recent article in the July issue of the Journal of the American College of Surgeons (full reference below) looked at the risk factors for developing a breast abscess.
It is a case control study of 68 patients with a primary breast abscess. Several (36/68) developed a recurrence as defined by the need for repeated drainage within 6 months.
Univariate analysis indicated that smoking (odds ratio [OR] 8.0 [95% CI 3.4 to 19.4]), obesity (OR 3.6 [95% CI 1.5 to 9.2]), diabetes mellitus (OR 5.7 [95% CI 1.1 to 54.9]), and nipple piercing (OR 10.2 [95% CI 1.3 to 454.4]) were significant risk factors for development of primary breast abscess.
Recurrent breast abscess occurred in 36 (53%) patients. Multivariate logistic regression identified significant OR for an increase in recurrence related to age (OR 1.08 [95% CI 1.01 to 1.15] per year), smoking (OR 14.73 [95% CI 3.18 to 68.22]), surgical treatment (11.94 [95% CI 1.08 to 131.72]), and a decrease in recurrence after MRSA infections (OR 0.02 [95% CI 0.00 to 0.72]).
I think perhaps this article has too small a number of individuals, but find their numbers interesting.
The eMedicine overview (second reference below) does not even address possible infections from nipple piercing, suggesting:
Causes of primary breast infections are most likely to be Staphylococcus aureus and streptococcal species. Nonpuerperal abscesses typically contain mixed flora (S aureus, streptococcal species) and anaerobes.
The eMedicine article does recognize a correlation between breast infection and smoking:
A study by Schafer et al found a significant correlation between cigarette smoking and subareolar breast abscess.12
So while the article may have a small number of individuals, it is probably safe to say that being overweight, having diabetes mellitus, and smoking all make your risk of having a breast infection higher. By how much is more difficult to say.
Risk Factors for Development and Recurrence of Primary Breast Abscesses; Vinod Gollapalli, Junlin Liao, Amela Dudakovic, Sonia L. Sugg, Carol E.H. Scott-Conner, Ronald J. Weigel; Journal of the American College of Surgeons - July 2010 (Vol. 211, Issue 1, Pages 41-48, DOI: 10.1016/j.jamcollsurg.2010.04.007)
Breast Abscess and Masses; eMedicine article, May 13, 2010; Andrew C Miller, MD, Tajinderpal S Saraon, MD, and Mark A Silverberg, MD, FACEP, MMB