Self-report studies are known for sometimes being inaccurate, chiefly because too much responsibility is placed on the respondents. Oftentimes people forget, overestimate, underestimate or do a host of other things that result in partially or wholly inaccurate reporting. There's also something known as The Testing Effect; a situation wherein people answer a question a particular way because they feel it is the answer the test-giver is looking for. So, in sum, self-report studies aren't really the best source for data collection. I mention all of this because it was a self-report study that researchers recently used to link symptoms of depression with the development of diabetes in older adults.

Researchers from Northwestern University studied a group of over 4,600 participants who were at least 65 years of age or older and did not have diabetes at the outset of the experiment in 1989. Each year for ten years, the participants were evaluated for symptoms of depression, based on the participants' response to survey questions. Also recorded each year were clinical measures that would indicate the development of diabetes.

The researchers found that as the participants reported feelings of depression as the years went on, an increase in participants who developed diabetes occurred.

Now, aside from the problems related to the self-report study, I also wonder how the researchers can be so sure that the depression lead to the diabetes. In fact, it seems to make more sense (at least to me) that the diabetes led to the depression. A person contracting a life-altering disease such as diabetes certainly wouldn't add joy to their life, so it stands to reason that it would instead make them a bit -- if not very -- depressed. I'm no scientist, but this correlation seems to make much more sense to me.

Research conducted by an anthropology professor at the University of California Irvine calls into question the imperfect science behind labeling ethnic groups for classifying and studying chronic illness. Paying specific attention to the problematic nature of linking health inequalities and so-called predisposition to genetic variation rather than social factors such as poverty and access to adequate health care, the research raises questions about the established, inexact methods of establishing race and ethnicity.

After following the trail of DNA samples from when they were first donated by people living along the US-Mexican border, to the eventual publication of findings based on these samples in scientific journal, the researchers found that the resulting data utilized by U.S. and British scientists used social and historical explanations -- not biological differences -- to define race and ethnicity for their research. Arbitrary labeling systems such as these, and their attendant genetic studies, are behind data suggesting that certain ethnic groups are predisposed to chronic illnesses like diabetes. In fact, this very thing was suggested of Mexican Americans, sparking international debate.

The researchers fear that the current methods of labeling race for research purposes will produce dissimilar and inconclusive results from study to study. This could effect the way a disease such is diabetes is treated for any given race, as it may be viewed as a genetically predisposed problem, for example, when in reality the problem is rooted more in social inequity.