Association between overweight and characteristics of young adult students: support for nursing care

OBJECTIVE: to verify associations between overweight and the characteristics of young adult students to support nursing care. METHOD: case-control study conducted with young adults from public schools. The sample was composed of 441 participants (147 cases and 294 controls, with and without excess weight, respectively). Sociodemographic and clinical characteristics were collected together with exposure factors and anthropometrics. Multiple logistic regression was used. The study received Institutional Review Board approval. RESULTS: statistically significant association with overweight: non-Caucasian, having a partner; weight gain during adolescence, mother's excess weight, the use of obesogenic medication, augmented diastolic blood pressure, of abdominal circumference and waist/hip ratio. In addition to these, schooling and weight gain during childhood were also included in the multivariate analysis. After adjustment, the final model included: having a partner, weight gain during adolescence, augmented diastolic blood pressure and abdominal circumference. CONCLUSION: the analysis of predictor variables for excess weight among young adult students supports nurses in planning and developing educational practices aimed to prevent this clinical condition, which is a risk factor for other chronic comorbidities, such as cardiovascular diseases.


Introduction
Overweight and obesity are conditions on the rise among young adults and nurses need to work on the prevention of these conditions to improve the quality of life of this population.
One report conducted by the World Health Organization (WHO) states that obesity is the cause of death of 2.8 million people a year and 12% of the current world population is considered obese. A total of 26% of the adults on the American continent is obese; the region in which the condition is the most incident in the world. The WHO's department of statistics reports that obesity doubled between 1980 and 2008 around the world (1) .
In Brazil, excess weight is considered an important nutritional disorder. Accumulation of body fat often begins during childhood and adolescence and persists into adulthood, possibly leading to physiopathological effects in adulthood (2) .
The determination of overweight and obesity results from a set of factors that constitute the lifestyle of modern populations, consuming increasingly processed, energy-dense foods rich in sugar, fat and sodium, with calories above individual needs. This imbalance stems partly from changes in dietary patterns, combined with reduced exercise in both work and leisure activities (3) .
It is important to stress multiple and heterogeneous determinants (biological, historic, ecological, social, cultural and political factors) of overweight.
Environmental and social causes are in the sphere in which individuals have little or no ability to interfere (4) .
It is apparent, in this context, that obesity is not a problem of developed countries only; it also affects a portion of less favored populations. Therefore, government authorities as well as nurses and other health care workers need to mobilize to establish priorities and strategies to promote health and control health conditions.
It is worth noting that the emphasis concerning this public health problem in the school context has been directed to specific groups: children and adolescents (5)(6)(7) .
The young adult population (20 to 24 years old) still attending school, however, has not been included in research, which justifies this study. 11516679-3.

Results
The description and analysis involved the predictor variables (sociodemographic, clinical-epidemiological, and exposure aspects) and outcome variables (overweight or obesity), as presented in Table 1.
As shown in Table 1, most participants from both groups (case and control) were aged between 20 and 22 years, were Non-Caucasians, had no partner, had a family income of up to two times the minimum wage, did not live in slums, were attending 1 st or 2 nd year of high school, and parents had attended up to eight years of school. Only the sex variable showed difference between groups: women were predominant in the case group while men predominated in the control group. After identifying variables p<0.20 we proceeded to the multivariate analysis with the adjustment stage (Table 3).
When analyzing the effect of sociodemographic

Discussion
Having a partner, considered in this study as being in a stable union or married, was statistically associated with overweight/obesity in both the bivariate and multivariate analysis, and remained in the final model. One study (10) conducted with the employees of a federal university verified that marital status was strongly associated with overweight and obesity, and prevalence was lower among single individuals, 41.8 and 1.8%, respectively. Another study (11) found significant risk estimates (p<0.001) among men with a partner (PR=1.88). Another study (12) conducted with adults in Maranhão verified that not having a partner was associated with lower prevalence of abdominal obesity (PR=0.28).
We suggest that marriage may influence weight gain due to changes in social behavior, which lead to increased caloric ingestion, due to foods rich in fat and sugar and decreased energetic expenditure, as a consequence of neglecting more rigorous physical activities and increased visits to restaurants and coffee shops as leisure. Additionally, couples tend to concern less with their self-image. approximately one in every two obese children become an obese adult while only one in ten non-obese children become obese in adulthood (13)(14) .
With regard to weight gain during adolescence, Some studies report that obesity during childhood and adolescence is a concern because, if not controlled, the prognosis is increased morbidity and reduced life expectancy (15)(16) , as it is associated with dyslipidemia, hypertension, glucose intolerance, psychosocial difficulties and increased risk of persistent obesity during adulthood (6) .
The literature usually addresses hypertension as a consequence of weight gain (7,17) . In this study, an association between hypertension as predictor variable and overweight/obesity as outcome could be identified.
Both systolic and diastolic blood pressures were verified to check for hypertension and only the latter showed statistic significance as outcome, both in the bivariate and multivariate analysis, so that diastolic blood pressure remained in the final model. Hence, this study shows that hypertensive individuals are seven times more likely to develop overweight/obesity.
One cross-sectional study (18) applied multiple logistic regression to verify the variables associated with overweight and obesity and the adjusted analysis showed that hypertension was one of the variables that were statistically associated (p<0.05) with overweight.
Hypertensive individuals were 3.3 times more likely to develop overweight than normotensive ones. The analysis of obesity showed that hypertensive individuals were five times more likely to develop abdominal obesity that normotensive individuals.
One study (11) (12) . Based on this fact, we investigated the association between this variable and the outcome, which was detected in the bivariate and multivariate analyses.

Conclusion
After bivariate analysis and adjustment of the multivariate analysis, the following variables remained in the final model: having a partner, overweight during adolescence, diastolic blood pressure indicating hypertension and augmented abdominal circumference.
All the variables tested in this study were subject to be statistically associated with overweight/obesity because they were based on various studies developed on this topic. One has to consider, however, the age interval of this young population addressed in this study. Many of the predictor variables would require longer periods to fully manifest. Other factors may have contributed to a lack of association: e.g. the accuracy of the answers provided by the participants was not take into account.
The conclusion, therefore, is that the analysis of the predictor variables for excess weight in young adult students support nurses in the planning and development of educational practices aimed to prevent this clinical condition, a risk factor for other chronic comorbidities, such as cardiovascular diseases.