Risk Factors for Type II Diabetes Mellitus: an Integrative Review

1 Nurse, Master of Nursing at the Graduate Program of Nursing-PPGENF/ UFPB, Member of the Group of Studies and Research in the Treatment of Wounds-GEPEFE, Federal University of Paraiba, *. 2 Nurse, Member of the Group of Studies and Research in the Treatment of Wounds-GEPEFE, Federal University of Paraiba, *. 3 Nurse, Master of Nursing at the Graduate Program of Nursing-PPGENF/ UFPB, Federal University of Paraiba, *. 4 Graduate Student of Nursing, Member of the Group of Studies and Research in the Treatment of Wounds-GEPEFE, Federal University of Paraiba, *. 5 Doctor, Geriatrics Professor at the Federal University of Paraiba (UFPB); Preceptor of Internal Medicine Residency at the University Hospital Lauro Wanderley-UFPB; Master of Nursing at the Graduate Program of Nursing-PPGENF/UFPB, *. 6 Integrated Residency in Multiprofessional Care Hospital, Federal University of Paraiba, Paraiba, PB, Brazil. 7 Nurse, Doctor of Nursing, Department of Nursing-DENC/UFPB, Member of the Group of Studies and Research in the Treatment of Wounds-GEPEFE, Federal University of Paraiba, *. *: João Pessoa, Paraiba, Brazil


Introduction
Over the years, due to the accelerated globalization, urbanization and population growth, there have been several changes in the lifestyle of people in society. Stress, consumerism, alcohol, smoking, sedentary lifestyle, excessive calorie diet and lack of physical activity in their lives are some of the possible factors that can trigger diseases, including diabetes mellitus (DM).
The Brazilian Society of Diabetes describes the DM as a syndrome of multiple etiology of metabolic disorders caused by the lack and/or deficiency of insulin, which causes a chronic condition that requires the person affected by DM continuous change in both the lifestyle as adapting the disease [1].
According to the International Diabetes Federation, in 2015, there were in the world 415 million adults affected by the problem, and, in 2040, there shall be 642 million people with diabetes. In addition, there are projections that one in two adults have undiagnosed diabetes, representing high risk of developing complications with higher costs, since the disease has an economic burden of US$ 673 billion in investments in health, corresponding to 12% of the total invested in health in the world. The DM also carries high mortality rates, with estimates that every six seconds a person dies from diabetes [2].
In accordance with the 2015-2016 Brazilian Guidelines for Diabetes, in 2014, 11.9 million people, aged from 20 to 79 years, were affected by DM, and estimates suggest that by 2035, this number may rise to 19.2 million [1].
Based on the ADA and the World Health Organization, the Ministry of Health classifies Diabetes Mellitus in types: I. Destruction of beta cells that produce insulin due to an error in the immune system and II. There is a defect in the secretion of insulin associated with a resistance to the substance, predominating in 90% of cases of diabetes. The gestational diabetes, not fully understood, can occur due to hyperglycemia, firstly diagnosed during pregnancy, and may disappear, or not, after delivery. There are other types characterized by genetic defects associated by disease or drugs [1].
The development of type II Diabetes Mellitus (T2DM) relates to the predominance of genetic factors associated with inappropriate lifestyle standard [3], with a prevalence of 90% to 95% of cases [1].
Obesity, physical inactivity, hypertension, hyperlipidemia, gestational diabetes history, increasing age, differences in ethnic groups and hereditary factors are factors of risk that can contribute to the development of type II diabetes mellitus [4].
Therefore, knowing the factors of risk that predispose to the development of T2DM is important to health professionals. That knowledge enables professionals who work in Basic Health Units identifying the user predisposed to develop T2DM, and reducing the possibility of the disease onset.
In Brazil, the healthcare professional from primary care is more likely to identify risk factors for DM, once their activities are performed in the first level of health assistance, promoting a longitudinal care [5]. Primary Healthcare is characterized by a set of individual and collective health actions comprehending health promotion and prevention of diseases, diagnosis and treatment that provides holistic and longitudinal care, by means of qualified multiprofessional teams acting in basic healthcare facilities [5].
The Basic Health Units (BHU) consist of a multidisciplinary team, composed by: doctor, nurse, dentist, Community Health Agents and other professionals. They use methodologies and tools for organizing the work process, such as receptiveness, spontaneous demand, and consultation of risk groups for chronic diseases, comprehensive care and home visits in order to meet the health needs of the population [6]. The nurse, as a member of that team, uses, as the main strategy, the nursing consultation, being important for health education [7].
Given the need to advance in the knowledge about factors of risk for type II diabetes mellitus, the following leading question emerged: What are the factors of risk that may contribute to the development of type II diabetes mellitus published in national and international studies? Thus, the objective of this study was to identify the evidence available in the literature on the factors of risk for type II diabetes mellitus.
The justification of interests in this integrative review is the progressive increase in T2DM cases in the world, and the social impact of that disease, compromising the quality of life. The consequence of that disease results in increased demand in health services, causing high rates of visits, hospital admissions, periodic exams and availability of medication for frequent and continuous use. Considering that, prevention, treatment and control of diabetes are difficult, because they require constant care, often neglected by the health team, family or even by the own person affected by T2DM.

Material and Method
This is an integrative review, a type of study that examines the scientific literature with the intention to integrate and promote knowledge about a particular subject [8].
Its development occurred from May to July 2016 in the following databases: Scientific Electronic Library Online (SciELO), Latin American and Caribbean Health Sciences (LILACS), US National Library of Medicine National Institutes of Health Medical Online (PUB-MED) and Scopus. The search of the journals at the mentioned databases was performed using the terminology in health found in Descriptors in Health Sciences (DeCS).
Thus, DeCS identified the terms "Diabetes Mellitus Tipo 2" or "Type 2 Diabetes Mellitus" and "Fator de risco" or "Risk factor". Those descriptors, combined with the Boolean operator "and", were used, conditioning their presentation in the title of the work in order to refine the studies that addressed only the selected theme. After searching in the databases there was conducted the reading of the titles and abstracts to identify whether they contemplated the objective of the review. Given the relevance of the study, the next step was to verify if the text was fully available. There was exclusion of studies that had text and abstract with relevant theme, but were not complete. Thus, it was possible to identify 504 publications.
In order to select the sample, the studies had to meet the following inclusion criteria: publications in the form of article or review with full text, having as theme the factor of risk for type II Diabetes Mellitus,   Figure 1. Therefore, the final sample consisted of 14 articles for the review analysis. Among them, six were in English, two, in Spanish, and six, in Portuguese. It is noteworthy that the commitment to the ethical aspects constitutes the citation of the analyzed authors.
In order to extract the main data, there was preparation of an instrument that had information on Journal/Year/Authors, Journal title, Objectives, Study/Qualis Design, Factor of risk and Conclusion. The results and analyzes are presented below.

Results
The study sample consisted of 14 publications that contemplated the factors of risk for type II diabetes mellitus within the prescribed period. Regarding the type of study, cross-sectional studies prevailed, with eight (57%) publications. Regarding Qualis, most of them belonged to category A, with seven [50%); six (42.8%) studies of the review had no Qualis and one (7.2%) belonged to Qualis B. Regarding the target population of each review article, Table 1 shows the results. Table 2 shows the results of the synthesis of the articles selected for the integrative review.

Discussion
The Ministry of Health uses, in the screening of asymptomatic adults for type II diabetes mellitus, the following factors of risk: age>45 years, overweight (Body Mass Index BMI>25), central obesity (waist circumference>102cm for men and >88 cm for women measured at the height of the iliac crests), family history [mother or father] of diabetes, high blood pressure (>140/90mmHg), HDL d"35 mg/dL and/or triglycerides e"150 mg/dL, macrossomy or gestational diabetes history, previous diagnosis of polycystic ovary syndrome and cardiovascular, cerebrovascular or peripheral vascular disease [9]. In T2DM, the most common factors of risk in adults are overweight and family history of DM [10]. The International Diabetes Federation advert that the factors of risk responsible for the development of type II diabetes mellitus are overweight, family history of diabetes, unhealthy diet, increasing age, high blood pressure, ethnicity, physical inactivity, glucose intolerance, gestational DM history and malnutrition during pregnancy [11]. There is no unified standardization for the risk fac-tors of DM2 used in practice, in this review the objective was to discuss the factors found, emphasizing the population in each study. Given the studies analyzed in the review of T2DM, two addressed the factors of risk in children. The first [12] brought as a factor of risk a family history of type 2 diabetes, high BMI and high blood pressure. On the other hand [13], in line with the first, investigated overweight and high blood pressure; however, it did not investigate family history with DM as a risk factor. Those results corroborate the ones standardized by the American Diabetes Association (ADA) [12]. The Ministry of Health calls attention to the increasing number of cases of T2DM in children and adolescents [10]. This reality is not only Brazilian, but worldwide [14][15].
Regarding adolescents, a study identified the following factors of risk for T2DM: high blood pressure, overweight, high blood glucose, physical inactivity and family history of DM in a population of adolescents in Fortaleza, Brazil, showing that 39% had at least two factors of risk for T2DM [16]. That was the only study found on this population based on the data used in this review. However, an intervention study with adolescents at risk for T2DM detected those same factors, which promoted a discussion about the importance of educational actions in health instead of promoting knowledge for the target audience, contributing, thus, to changes in lifestyle of that risk group [17]. Thus, this review suggests there are still few publications on T2DM in adolescents and children, but the progression of the disease becomes a major concern worldwide. As for college student, there were several factors of risk for T2DM [18][19]. Stressing [18] physical inactivity, overweight, obesity, high blood glucose and arterial hypertension, pointing to physical inactivity as the most prevalent risk. Lately, one may observe that university students have a vulnerability to develop T2DM caused by a sedentary lifestyle, overweight, limited physical exertion, due to the use of technologies and adherence to fast and few healthy food habits [20]. Another study [19] reveals that physical inactivity was a risk factor responsible for 75% of the sample, the most prevalent, validating the previous data. For other risk factors investigated in college students through two studies, only one study [19] pointed out the family history of diabetes in 45% of the sample; whereas other study [18] did not investigate that risk factor. Having a first-degree relative with diabetes means a risk ten times greater of developing T2DM [21]. In another study, that factor represented a double risk in the development of T2DM [22].
From the point of view of the prevalence of factors of risk in health workers, studies [23][24] indicate nursing as the most vulnerable profession to develop T2DM. Articles attribute this to workload, which hampers both the practice of healthy eating habits, as the incorporation of physical activity [22][23]. Statistically significant risk factors were overweight/obesity in a study [23] and abdominal obesity, physical inactivity and abnormal waist circumference [24], factors observed in other studies [4,25]. On the other hand, an international study with health workers observed that the risk for T2DM in nurses was relatively low, due to health and lifestyle knowledge acquired in their educational background [26].
A study with patients of an emergency room found that advanced age, heredity and abdominal obesity are risk factors for T2DM [22] , also found in other studies [27][28], which point to hunger and malnutrition in childhood as possible reasons for T2DM, different from those found in the literature [22].The International Diabetes Association points out the bad nutrition in pregnancy as a factor of risk for T2DM, but does not refer to that nutrition during childhood [11].
A study with FHS users found that 10.3% had high risk to develop T2DM [4]. In Amarante, Portugal, the risk was similar, 11.3% [29]. On the other hand, in southern Brazil, the high risk was 17%, almost the double [30]. All those studies used the  [4]. Other studies have widely used that tool [27,[30][31]. The International Diabetes Federation recommends the use of that tool for it is practical and quick in the screening of the risk for T2DM [11].
A study with Japanese industrial workers found that participants with a family history of T2DM had 80% of risk to develop the disease compared to those without a heredity history, so there is no association of that risk with obesity and physical inactivity [32]. A study with workers at a Brazilian industry showed that the sedentary lifestyle, poor diet, weight gain and the history of T2DM in the family represented the most striking factors of the study for the development of T2DM [25].
Studies [33][34][35][36] analyzed the factors of risk in a population of adults and observed that the risk for developing T2DM mainly relates to gender, age, family history of T2DM, physical inactivity, hypertension, high BMI, modified triglycerides, obesity/ overweight and urban residence, factors also found in the Arab population described in an integrative review [14]. This review identified and discussed most of those factors; however, two must have a better emphasis. Living in urban areas is a higher risk for T2DM, compared to rural population due to the fact that their populations have sedentary lifestyles and unhealthy eating habits [14]. Nevertheless, a study with the rural population identified that participants had 21% of high risk of developing T2DM [28], which leads us to infer that there is also a vulnerability in that population. Regarding the high level of triglycerids, it is a parameter that can only be confirmed in laboratory tests, being modified by changes in lifestyle; thereby another study also mentioned triglycerids as a statistically significant risk factor for DM2 in the research [37].
Literature evinces that the risk factors of modifiable nature for DM2 are the primary responsible for the high risk of developing DM2 [28].

Conclusion
The studies on type II diabetes mellitus enabled identifying and discussing a wide range of factors of risk, clearly showing which may favor the development of the disease and the possible means to build preventive and promotional strategies to groups prone to develop the problem.
Thus, the analysis reflect relevant aspects that can guide health professionals, especially nursing professionals engaged in the Basic Health Unit who keep direct contact with patients at risk of developing such disease.
There should be development of further studies to examine the factors of risk in different populations in order to identify more associations between the analyzed factors, especially those of modifiable nature.