There are several risk factors that increase an individual’s chance of health problems.  Specifically, one’s lifestyle, environment and genetic predisposition may serve either as a risk factor or a protective factor for different health problems.  This essay is going to focus on risk factors for obesity.

One risk factor for obesity is living a sedentary lifestyle. A large-scale study (15000 people) was carried out in the European Union to determine the relationship between sedentary behaviour and obesity. 15 different countries were studied to avoid cultural bias in the sample.  The study was a structured interview, asking about time spent in various physical activities.  In addition, BMI measurements were taken. There was a strong correlation between those who had high amounts of sedentary time (35 hours per week) and obesity and an inverse correlation for those with high amounts of physical time.

The increased availability of fast food, in combination with our sedentary lifestyle, is also a risk factor.  A sedentary lifestyle alone cannot be held responsible for the obesity epidemic.   A change in our diets and the way we eat – not with family, but on the run – has contributed to obesity.  Joseph et al looked at the rising trend of eating fast food in India in a sample of high school boys.  The study looked at three private schools in Southern India.  The study was based on semi-structured interviews and a questionnaire.  In their study, 15% of the boys were overweight or obese. The researchers found that increased consumption of fast food was correlated with being overweight or obese. It should be noted that the study is correlational and does not clearly indicate a cause and effect relationship.  In addition, the study is not prospective; it only looks at current weight and attempting to link it to fast food. It does not account for the child's birth weight, parental eating habits or regular exercise patterns.  Because these questions were asked using a questionnaire, responses are imprecise and may be open to memory distortion or optimism bias. However, combining interviews with the questionnaire triangulates the data and increases the credibility of the findings.

Finally, stress plays a role in obesity. Stress causes the release of the stress hormone cortisol, which triggers the release of triglycerides from the liver and relocates them to fat cells in the abdomen. Cortisol also increases appetite. Koch carried out a study in Sweden to see if family stress was correlated with obesity in 5-year-olds.  The study had a sample of over 7000 families.  The families filled out questionnaires to measure the level of stress in four areas: serious life events, parenting stress, lack of social support and general anxiety. The study found a correlation between the level of stress experienced by the family and the risk of obesity. This is an important finding because it means that simply changing eating behaviours is not enough; instead, families need to be given support to manage stress.

There are several difficulties with studying risk factors for health problems, that are not unique to obesity research.  First, all of the studies above are correlational in nature.  The inability to conduct experimental research leads to correlational findings which cannot establish a true cause and effect relationship. The studies lack the ability to isolate variables and have controls.  Several other variables, including genetics, may play an unknown role in the findings. In addition, it is not possible to isolate one’s sedentary life study from one’s level of stress, socioeconomic status or attitudes about food.  Many correlational studies suffer from bidirectional ambiguity. It is not clear to what extent a sedentary lifestyle leads to obesity – or obesity leads to a sedentary lifestyle.  This would be best addressed by prospective longitudinal research, which is difficult to carry out. It could also be that the two variables work on a positive feedback look in that a moderately sedentary lifestyle increases weight which then increases the sedentary lifestyle.

Although the use of questionnaires allows for large sample sizes, the data collection in many of these studies is problematic.  Structured interviews or questionnaires ask participants to self-report their behaviours.  In a structured interview, the social desirability effect may play a role, where a person’s responses are affected because they don’t want to be seen in a negative light.  Optimism bias is also a problem. We tend to overestimate our healthy behaviours.  We do not have a good memory of how much we actually exercise, the calories we consume or the amount of time we spend doing other healthy activities (such as sleep).  Finally, there are assumptions made in the research which could be challenged.  One of them is that the BMI is a valid measure of obesity.  This has been challenged as an inadequate measure of obesity, which may lead to some body-shapes incorrectly being diagnosed as obese.  This means that the findings of the studies could be challenged.

The research on risk factors indicates that there are many different reasons for the obesity epidemic.  It is difficult to know the level to which these factors interact and if some risk factors are more important than others.