Vitamin D deficiency is becoming a worrying problem in Saudi Arabia and worldwide [1, 2]. It has been recognized as an international public health problem because of its prominent role in the most common medical diseases related to the skeletal system [3, 4]. Vitamin D is a fat-soluble vitamin that is vital to bone health and increases the absorption and metabolism of calcium and phosphorous. The primary role of vitamin D is to preserve the balance of calcium and phosphorus, which is essential for healthy bone mineralization. Hence, the most prevalent disorders linked to vitamin D deficiency include osteoporosis, osteomalacia, and rickets in children. It improves the small intestinal epithelial cells' capacity to absorb calcium, controls how much phosphorus is absorbed from meals, and accelerates calcium reabsorption from the glomerular filtrate [5, 6]. Illnesses, such as multiple sclerosis, senile dementia, and schizophrenia, are strongly correlated with vitamin D insufficiency. Additionally, the renin-angiotensin-aldosterone pathway's stimulatory effects imply an association between a vitamin D deficit and the occurrence of cardiovascular diseases [7]. It should be highlighted that reduced incidence rates of colon, breast, ovarian, renal, pancreatic, and other cancers are significantly correlated with greater serum levels of 25-hydroxyvitamin D [8].

Many studies have reported that sunlight is the primary source of vitamin D [9, 10]. Despite this fact, vitamin D deficiency is unexpectedly higher in countries with a sunny climate, such as Saudi Arabia, Egypt, Oman, and the United Arab Emirates [11]. Babelghaith et al. [12] pointed out that although exposure to sunlight is a significant factor in the human body's production of vitamin D, vitamin D insufficiency is most common in some of the world's sunniest regions. Nevertheless, several reasons have led to Saudi Arabia's dangerously low vitamin D levels. The people of Saudi Arabia generally live indoors because of the country's extreme heat despite the belief that a deficiency in vitamin D is caused by Muslim communities' traditions of avoiding sun exposure.

Ghada reported that the risk factors for vitamin D deficiency include low socioeconomic level, female gender, multi-parity, season, conservative clothing style, and living in urban areas [2]. Siddiqui [13] assumed that sun exposure in Saudi Arabia is limited because women wear abaya, hiding them completely from head to toe. Christie et al. [14] reported, in their study, that students showed minimal awareness of vitamin D that it is crucial for the health of musculoskeletal development and that sunlight is beneficial.

As sunlight exposure is the main source of vitamin D, the efficiency of the conversion of 7-dehydrocholesterol to vitamin D3 is dependent on many factors, like the time of the day, season of the year, nature, skin color, and age. Other sources of vitamin D have relatively little vitamin D levels and these are found in natural food, such as seafood, shrimp, mushrooms, egg yolk, and fortified milk [15]. Vitamin D is stored in fat cells and is transported to blood circulation by vitamin D-binding protein. Vitamin D3 (cholecalciferol) is biologically inactive and should be metabolized to 25-(OH) D3 in the liver and then to 1.25-dihydroxycholecalciferol in the kidney, which represents the biologically active form of vitamin [16, 17]. Assessing the knowledge, attitudes, and practices of the general population is essential to identify any gaps in their understanding and approach toward vitamin D deficiency status. The results obtained from the general population regarding knowledge and attitudes towards vitamin D could motivate policymakers to implement awareness programs or interventions to improve good practices and knowledge about vitamin D . This study aimed to assess knowledge, attitudes, and practices regarding vitamin D deficiency among the general adult population in the Qassim region of Saudi Arabia.

A total of 336 individuals from the targeted sample (n=377) responded to the survey, achieving a response rate of 89%. Table 1 shows the general characteristics of participants aged 18 to 60. The mean age in years of participants was 35.52 (13.54%). Approximately 95.8% of participants were Saudi, with the majority of participants (73.2%) being males and 26.8% being females. A bachelor's degree was held by slightly more than half of the participants (59.2%).

Exposure to sunlight is a crucial source for obtaining vitamin D. Various factors, including the aging process, having dark skin, and applying sunscreen, can diminish the skin's ability to produce vitamin D [9, 18-24]. Vitamin D can also be acquired through dietary sources, like egg yolk, fish, and liver. Certain foods, like milk and cereals, are also enriched in vitamin D [25]. During this study, an evaluation was conducted to gauge participants' practices concerning vitamin D intake and their sun exposure habits. The findings indicated that more than half of the participants exposed themselves to sunlight on a daily basis. This aligns with the outcomes of a cross-sectional study conducted among females in Jeddah city [21]. Our results demonstrated a higher percentage compared to a study carried out in Riyadh, which aimed to assess the general population's knowledge, practices, and attitudes regarding sun protection and its association with vitamin D deficiency. In that study, it was revealed that less than half of the participants (46.4%) exposed themselves to sunlight daily [12].

In our study, we observed that a mere 12.5% of participants utilized sunscreen products with an SPF rate exceeding 15, and only 3.9% of this subgroup applied sunscreen on a daily basis. These outcomes are consistent with previous investigations conducted among females in Riyadh city [15]. Similarly, a study conducted by Christie [14] in Saudi Arabia, specifically among female students, revealed that the respondents exhibited insufficient knowledge regarding vitamin D. Furthermore, this study highlighted that the participants had restricted sun exposure, primarily because of the sweltering heat [14].

Vitamin D deficiency is known to be associated with various health conditions, including cancer, chronic diseases, and specific physical issues related to bone health. In our study, a substantial majority of participants (88.1%) recognized the crucial role of vitamin D in maintaining bone health. However, less than half of the participants (45.5%) believed that vitamin D deficiency could also contribute to other health problems, such as cardiovascular issues, diabetes, depression, and cancer. This finding aligns with a study conducted in Riyadh [12], which reported that only 48.4% of subjects were aware of this association. In a cross-sectional study conducted in the United States of America, researchers found evidence linking vitamin D deficiency to an elevated risk of cardiovascular disease [18]. Nevertheless, our study's awareness rate was higher than that of previous research, including one study conducted among Saudi females where approximately 25.6% provided the correct response regarding the significance of vitamin D [15]. Additionally, a study carried out in Australia indicated that 76% of subjects acknowledged vitamin D's role in maintaining bone health [20].

For most individuals, the primary source of vitamin D is exposure of the skin to Ultraviolet B (UVB) rays from sunlight. Additionally, vitamin D can be obtained through dietary sources, like eggs, fatty fish, and vegetables, or via supplementation [19]. In our study, a significant portion of respondents (83.9%) indicated that they meet their vitamin D requirements through sunlight exposure, followed closely by vitamin D supplements (80%). A smaller percentage reported obtaining vitamin D from dairy milk (26.78%), fatty fish (14.88%), and eggs (30.95%). These findings suggest that participants had a good level of knowledge and awareness regarding the importance of sunlight in obtaining vitamin D. However, it is worth noting that their actual sun exposure practices may not align with this knowledge, as they did not engage in sufficient sun exposure. These results are consistent with a previous study [12], where 91.5% of subjects identified sunlight as the primary source of vitamin D, followed by vitamin D supplements (73.4%). Similar findings were reported in a French study, where 72% of participants recognized sun exposure as the primary source of vitamin D [26]. However, in our study, only 22.6% thought that they were getting enough exposure to sunlight. This result is consistent with a study conducted in Egypt [27], where only one-third of the participants were exposed to sunlight. This low percentage of people willing to get enough exposure to sunlight is vital since it raises the risk of vitamin D deficiency in them.

While a significant number of participants in our study correctly identified sunlight and vitamin D supplements as sources of vitamin D, a smaller percentage accurately recognized food sources of vitamin D. Specifically, our findings showed the primary sources of information about vitamin D to be healthcare providers (45.5%), followed by family and friends (26.8%), and media (22%). The influence of healthcare providers in imparting knowledge about vitamin D is noteworthy, as they play a crucial role in educating patients and the general public. This finding aligns with a similar study conducted in Riyadh, where less than half of the participants (44%) acknowledged healthcare professionals as the primary source of their knowledge about vitamin deficiency [12]. Contrary to our results, some other studies found social media as the main source of information among the general population group [28, 29].

The results presented in Table 5 indicate that participants had varying perceptions about the protective effects of vitamin D supplementation against the deterioration of health in COVID-19 patients. Specifically, 31.3% of respondents believed that vitamin D supplementation could offer protection in this context, while 46.4% admitted being uncertain about its efficacy. Only 22.3% of participants responded correctly and reported that vitamin D supplementation cannot protect against health deterioration in COVID-19 patients. Interestingly, these findings contrast with the results of a Mendelian randomization study, which unexpectedly revealed that vitamin D supplementation does not confer protection against the deterioration of health in COVID-19 patients [22]. This discrepancy between public perception and scientific evidence highlights the need for clear and accurate communication of research findings to the public to ensure informed decision-making regarding health practices and supplements.

A notable finding in our study was the significant association between knowledge of vitamin D benefits and age (categorized as less than median 33 years and 33 years and more) (p = 0.004). Interestingly, this result contradicts the findings of a study conducted by Alamoudi, et al. [30]. Conversely, we did not observe a significant association between knowledge sources and age, nor between overall knowledge (benefits and sources combined) and age (p = 0.438 and p = 0.139, respectively). Remarkably, these results align with the findings reported in the study by Alamoudi, L. H et al. [30], where no significant associations were found (p = 0.62 and p = 0.63, respectively).

These variations in findings between studies may be attributed to differences in sample characteristics, study methodologies, or cultural factors. Further research and exploration of these associations are warranted to understand better the relationship between age and knowledge of vitamin D benefits.

Despite that the current study primarily focused on the general population in the Qassim region and the sample size was acceptable, the males constituted the majority of the study sample, so we believe it to be one of the study’s limitations. Also, the study was conducted in a limited area at a specific time, so the results could not be generalized to other populations. However, we recognize the importance of conducting further research on vitamin D deficiency to investigate potential gender differences.

The results of this study have revealed Saudis to have a basic understanding of vitamin D. However, they lack adequate awareness of vitamin D and its effects on the heart, diabetes, depression, and cancer, as well as poor sun exposure habits. The findings highlight the significance of implementing ongoing public education programs to raise awareness and information about the benefits of vitamin D.