Hypertension and Family History

I. Introduction

Family health histories are attempts to reveal patterns about the inheritance, genetically and behaviorally, of a particular lineage in terms of the risk of certain medical conditions. Health is determined both by genetic propensity to certain conditions and also lifestyle choices which may be communicated through family relationships. One benefit of conducting family health histories is the simple act of being more aware of health issues within the community, facilitating communication about health, and providing information that one can provide to health providers (O'Leary et al., 2011, p. 119). Additionally, family health history can provide a valuable tool for research and evaluation of the way certain conditions travel through family histories. The small sample size and close focus of family genograms make it difficult to evaluate broad questions of research concern. Instead of attempting to test a large conclusion, this paper will instead explore the genetic and familial effects of hypertension in the context of a specific family.

II. Literature Review

The data undeniable suggest that there exists an important familial element to hypertension. At the same time, however, there is increasing evidence that this relationship is not situated on a single locus gene linkage with hypertension. Single gene errors do seem to be associated with rare metabolic problems leading to hypertension, but the vast majority of cases occurs in individuals with biochemical and physiologic traits in normal ranges of variability (Kardia, 2000, p. 32). Even with particular patterns of gene distribution that indicate a susceptibility to hypertension, as determined by studies of population genetics, the environment plays a crucial role. One of the most important aspects in the determination of individual risk of hypertension is in fact the interaction between a particular genotype and the environment. Specifically, studies like Hunt at al. (as cited in Kardia 2000) evaluate the relationship between a particular genotype, sodium reduction, and weight loss in terms of mitigating the risk of hypertension, finding that sodium reduction decreased the risks of hypertension in one genotype but not another (Kardia, 2000, p. 35). Genetics adjust the relevance of the context and vice versa; the important factor is in the interaction less than either on their own.

One of the problems with increasing the level of context of evaluating the risks of hypertension is that it vastly increases the complexity of analyzing the research. The cause is clearly multidimensional, but the basis to support the research is scarce. One route to solving the problem is developments in large scale gene expression assays that would more clearly allow researchers to look for connections between environment and genetics (Kardia, 2000, p. 37). One possible alternate method would be the use of large scale datasets of family histories, which use the historical information of genetic similarity and resulting illnesses. Additionally, in a family living in the same location, they will have a general similarity in both genetic and environmental factors. Close family essentially replicates the life of a single individual, with relatively low variance, allowing clinicians to essentially have small sample sets for determining a person’s life course (Valdez, Yoon, Qureshi, Green, & Khoury, 2010, p. 72).

Screening tools are in general extremely sensitive to populations and have difficulty crossing over between radically different demographics. Family history, then, becomes useful because it is a way of assessing risk internally to a small community (Valdez et al., 2010, p. 75). Family history has long since been known to be effective in both predicting and guiding medical care for people who are at risk for single-gene disorders (Guttmacher, Collins, & Carmona, 2004, p. 2333), but it is more generally valuable from research perspectives too. At least, family history can increase the predictive value of genetic and other screening tests, leading to the imperative to refine means for gathering, storing, and interpreting the histories. Family history can become an important tool in use in public health, as suggested by epidemiological studies, in order to trace and understand broad-base trends (Valdez et al., 2010, p. 75).

From an individual perspective, family histories of hypertension can guide clinical interventions or screening for conditions that wouldn’t usually be done. For instance, despite the fact that the early detection of primary hypertension is critical to deter the development of organ damage, it is uncommon to do the more robust ambulatory blood pressure measurement in children (Malbora et al., 2010, p. 536). Parental blood pressure is found to be a strong determinant of blood pressure in their children, indicating that family histories of hypertension could lead to clinicians implementing increased screening. This would reveal problems with the blood pressure earlier than the standard blood pressure tests, perhaps making outcomes more positive over the life of the child (Malbora et al., 2010, p. 537).

III. Research Design

My research question is whether or not hypertension is heritable. The research suggests that it heritable, though not on a single gene, so we would expect to see that while it is prevalent throughout the family, it does not follow strictly mendelian patterns. The sample size is too small to produce results with any degree of significance, so we are mostly looking for visual or apparent patterns that could potentially be extended into triggers for further study.

In some cases, the extremely small sample size and the census nature of the sample would be a cause for concern. However, the virtue of family histories of this is that normal questions of generalizability don’t really apply as they are about the nature of the family itself. . The purpose of this sort of research isn’t to expand upon generalizable conclusions by itself, but rather, to provide a mechanism for determining patterns in specific families.

The more generalizable research questions are solved by the aggregation of this sort of data, as articulated in O’Leary 2011. In order for this generalizability to be possible, it is necessary that the data is interoperable. As much as part of the personal value is engaging in a process of exploration with the members of one’s family and that is benefited by contextual, information-rich questions, a key element of the medical utility of family health histories is that they be able to be used in a multiplicity of contexts and fit smoothly into the typical work flow of physicians (Hampton, 2005, p. 723). Much of the research on using individuals as tools for collecting their own family history focuses on creating simple, straightforward questions that would provide clean and useful data. The health history itself is complicated, but research is benefited by simple, clean data.

Accordingly, my research uses the booklets created by the genetic alliance, and takes their suggestion for the construction of a clear, accessible survey that will allow for productive research(""Family Health History"," 2013). The survey was sent to all adult and living members of the family, with three of the responses being undertaken by living persons on behalf of already dead ones. The surveys were sent with the understanding that they were optional, after having obtained verbal consent to send the forms by phone call. There was a self-addressed stamped envelope also sent, in order to ease the return of the survey. The response rate was extremely high, with 100% return of the surveys. This indicates the positives in engaging with a community the researcher is closely involved in. People trust members of their family and they will engage closely with them. Additionally, the two levels of contact likely increased the rate of response: the researcher both called and then mailed, with an extremely short survey and basically no barrier to submission.

IV. Results

(Table 1.1omitted for preview. Available via download)

The illnesses observed in the sample were diabetes, kidney disease, coronary artery disease, heart attack, stroke, ovarian cancer, colon cancer, high cholesterol, and hypertension. The cluster of illnesses that relate to the heart and blood pressure, including stroke, coronary artery disease, and heart attacks is unsurprising in a family with such a high rate of hypertension.

(Table 1.2 and Table 1.3 omitted for preview. Available via download)

As expected, the chart of familial relationships makes the hereditability of hypertension career. The disease is present in all four of the grandparents and in the vast majority (with only one aunt as the exception) of the next generation. In the present generation, the subjects are much younger (23-49) and therefore would be less likely on face to show symptoms of hypertension.

V. Discussion

As expected, the prevalence of hypertension does not a strictly mendelian pattern, but does very much demonstrate that hypertension is at least in part hereditary. It is also extremely prevalent in this health history, showing up in 2/3 of the people surveyed. Because we don’t have nearly as many individual subjects to be able to be certain what we are seeing is chance, this doesn’t prove anything. It is merely suggestive, particularly when the data is broken down by age and it is clear that 90% of the subjects over fifty have shown symptoms of hypertension. This is significantly higher than the national average, with 31.9% of adults age 20 or over having been treated for hypertension. Much like our sample, though, the rate of hypertension rises with age; 53.0% of nursing home residents have hypertension("FastStats: Hypertension," 2013).

Cardiovascular disease is the leading cause of death in Texas, with a death rate of 352.7 per 100,000 individuals of cardiovascular disease in 2000 (Deyhim & Granberry, 2004, p. 67). South Texas, however, have lower levels of mortality from cardiovascular disease, likely because Hispanics die less from hypertension than non-Hispanics, despite high levels of diabetes, obesity, and socioeconomic disadvantage (Deyhim & Granberry, 2004, p. 65). On that front the sample is also consistent; the high rate of cardiovascular disease and hypertension makes sense in the context of a Caucasian family.

VI. Conclusion

Occupational therapy is concerned with increasing the quality of life for patients dealing with physical, mental, or developmental conditions and allowing them to work toward those goals. For many medical conditions, early detection and treatment is critical to the success of occupational therapy, as it allows for more mild interventions intending to prevent further degeneration in the condition, as opposed to trying to repair damage. Family histories are an incredibly useful tool from that perspective, as it helps the occupational therapist determine what the life-path was for the patients close relatives. Family history can also help other clinicians screen such that there can be early engagement by occupational therapists. One recent study on patients on mechanical ventilators in hospitals found that early intervention lead to far better functional outcomes(Schweickert et al., 2009).

In terms of hypertension specifically, occupational therapy is valuable in helping patients move away from risky behaviors that accentuate their hypertension, such as smoking, low activity, and obesity. Hypertension can often be a comorbidity with other illnesses that reduce the level of activity for a patient, making a close awareness of hypertension and related concerns critical for any occupational therapist. Further research and education on hypertension among the general population would be a great benefit for the health of the country, as well as mitigating preventable death.

My suggestion for further research on family health histories is to focus even more on the interoperability of the collection of data. Specifically, I would focus more on developing regimes that would allow the collection of as much data as simply, and easily as possible. For instance, websites like http://familyhistory.hhs.gov are promising avenues, as they suggest a way in which data can be easily manipulatable, easy to anonymize, and easy to update. Family histories are undoubtedly an important tool in both clinical practice and medical research; facilitating methods of collection and aggregation can only be beneficial.

References

Deyhim, F., & Granberry, M. C. (2004). CARDIOVASCULAR DISEASE. Nourishing the Future, 65.

Family Health History. (2013). Genetic Alliance. Retrieved from http://www.geneticalliance.org/fhh

FastStats: Hypertension. (2013). FastStats Retrieved from http://www.cdc.gov/nchs/fastats/hyprtens.htm

Guttmacher, A. E., Collins, F. S., & Carmona, R. H. (2004). The family history-more important than ever. New England Journal of Medicine, 351, 2333-2336.

Hampton, T. (2005). Family health history. JAMA: The Journal of the American Medical Association, 294(24), 3075-3075.

Kardia, S. R. (2000). Context-dependent genetic effects in hypertension. Current Hypertension Reports, 2(1), 32-38. doi: 10.1007/s11906-000-0055-6

Malbora, B., Baskin, E., Bayrakci, U. S., Agras, P. I., Cengiz, N., & Haberal, M. (2010). Ambulatory blood pressure monitoring of healthy schoolchildren with a family history of hypertension. Renal Failure, 32(5), 535-540.

O'Leary, J., Edelson, V., Gardner, N., Gepp, A., Kyler, P., Moore, P., . . . Bowen, D. (2011). Community-centered family health history: A customized approach to increased health communication and awareness. Progress in Community Health Partnerships: Research, Education, and Action, 5(2), 113-122.

Schweickert, W. D., Pohlman, M. C., Pohlman, A. S., Nigos, C., Pawlik, A. J., Esbrook, C. L., . . . Deprizio, D. (2009). Early physical and occupational therapy in mechanically ventilated, critically ill patients: A randomised controlled trial. Lancet (London, England), 373(9678), 1874-1882.

Valdez, R., Yoon, P. W., Qureshi, N., Green, R. F., & Khoury, M. J. (2010). Family history in public health practice: A genomic tool for disease prevention and health promotion. Annual Review of Public Health, 31, 69-87.