Routine physical check-ups offer multiple health benefits that can lead to a longer, healthier life. Regular check-ups are used to assess the general health of individuals and prevent future illnesses . Check-ups give health care providers an opportunity to get to know their patients better , allow for early detection of health problemsat the beginning or early stages, and offer better treatment chances [3,4], and can be cost-saving . Despite the positives associated with regular check-ups, some argue there is no clear evidence to support the need of physical check-ups  while others believe that annuals increase diagnoses and medications but does not affect ways to decrease morbidity and mortality from diseases such as cardiovascular issues and cancer . Contrary to critics' arguments, physicals check-ups are still needed in order to continue to identify and detect diseases and other health issues that individuals experience early . By being at the forefront of these diseases and issues, physicians can provide individuals with the appropriate services or refer them to specialists and reduce patients’ concerns .
Previous studies have reported various barriers and facilitators associated with regular check-ups including socio-demographic characteristics (e.g., age, gender, income) [7,8,9], accessibility to health care services (e.g., health insurance, primary doctor, and living area) [10,11,12,13], personal history of cancer [14,15], and family cancer history . For instance, young adults between the ages of 18-26 with a usual source of care were more likely to utilize physical check-ups  and having health insurance increased the likelihood of routine check-ups . On the other hand, individuals in rural areas were less likely to have physical check-ups because obtaining a primary care doctor was difficult as physicians are typically in cities and more affluent suburbs, and having low income was associated with not seeing a doctor for check-ups because of cost . Individuals with a history of cancer were more likely to utilize check-ups than those without a history [14,15], but having a family history of cancer did not increase one’s routine check-ups use . Another facilitating factor includes having a history of physical check-ups. Labeit and colleagues (2013) concluded that individuals who visited a general physician in the past year were more likely to make an appointment for the coming year, suggesting that once the behavior of annual check-ups is initiated, the behavior will continue.
In addition to the literature supporting factors associated with physical check-ups, health literacy could be another critical factor to explain for an individual’s physical check-up [19,20]. For example, people with limited health literacy tend to have cancer screenings and immunizations less frequently . However, little is known about how health literacy is linked to physical check-ups. To our best knowledge, this is the first study to investigate the contribution of health literacy to the uptake of physical check-up. Hence, this study aimed to examine the levels of physical check-up uptake and factors associated with physical check-up with specific attention to the role of health literacy on physical check-up uptake in two age groups. In our study, health literacy was defined as an individuals’ ability to obtain, process, and understand basic health information in order to make responsible decisions regarding their health [22, 23, 24].
Andersen’s Behavioral Model of Health Services Use  guided this study. The Andersen model is commonly used in studies on a variety of different health services divisions and diseases, such as HIV, dental, and long-term care [26,27,28]. In addition, the model has been used to predict variables associated with health literacy [29,30,31].
According to the Andersen model, individuals’ access to and use of health services are explained by a function of three components of predisposing, enabling, and need factors . Predisposing factors are an individual’s social-cultural characteristics (e.g., age, gender, income, and living area). Enabling resources reflect condition making healthcare available to individuals (e.g., health literacy, education, health insurance, and primary doctor). Need factors are an individual’s beliefs on their health and access to services such as self-reported health and the number of diseases (e.g., cancer, depression, etc.) and personal and family history of cancer. Figure 1 shows the conceptual model of this study.