Cause of low white blood cell count?

For the second straight May, I underwent a full blood panel analysis coordinated by the Life Extension Foundation. The nurse at the lab withdraws something like 4-6 vials of my blood, and a couple of weeks later I get back a report with the results.

The report includes 55 different results that cover a broad spectrum of health indicia. Here is a paper explaining the test. 

Last year, 54 of my 55 results were in the "normal" range; this year, 53 of 55. In both years, most of the normal results were also within or near the "optimal" ranges provided by the LEF.

That's the good news. But I'm a guy motivated by bad news. One of the results that was "off" this year was my serum iron count. I can chalk that one up to eating way too much meat. My wife had decided that she would offer our toddler animal meat (mostly poultry and fish) most every meal. Me, being busy with this site, just ate whatever was being served. And that meant way more meat than normal for me. Plus, I hadn't donated blood in many months prior to this test. So the fix for me for this problem is simple: cut down on the meat, and donate blood regularly.

The problem that has me mystified, however, is a low white blood cell count both this year and last. The normal reference range is given in units of "x10E3/uL" and that range is 4.0 - 10.5. Last year, my WBC number was 3.3; this year, 3.4.

What could be causing my low WBC count? Last year, during the test, I was fighting a viral infection caught from my relatives. This year, I was fighting a pretty invasive poison oak infection. But shouldn't those circumstances have elevated my WBC?

Here is a page that talks about about some risk factors and recommended habits for low WBC. Given that the recommendation is "Personal Hygiene Changes", that could ring a bell for me. Aside from the systemic poison oak infection, I think I have chronic decay in a front tooth that is a false cap. My wife complains that I have chronic bad breath. I know the problem isn't my gums generally, or my diet. I think it's this tooth.

Also, I suppose given that I've been working out of my home for the past >1 year, and I've been a negligent bather, while spending much time working our land, that could have played a role.

With all of that introduction, does it seem that my solution for this WBC problem could be as simple as covering up when I'm working near poison oak, and showering and grooming daily? Your ideas and recommended action will be much appreciated.