**4. Discussion**

It has been suggested that, lifestyle and socio-cultural practices may be related to the high Vit D deficiency reported among the young recently in Qatar [25]. However, the relationship between Vit D deficiency and its impact on the health of the elderly is still lacking.

Unfortunately, there are no accurate figures for the confident determination of vitamin D deficiency in Qatar due to the geographical and/or demographical nature of studies conducted [41].

However, centred on data gathered from a review of the system, about 90% of the Qatari population may be deficient in serum levels of the vitamin. This exclusive study from the region tries to address the impact of age, diabetic status and dyslipidaemia on Vit D deficiency among the geriatric population.

This study found the existence of an extraordinary large number of Vit D deficiency (71.8%) among the elderly in Qatar, which may be attributed to their limited exposure to sunlight as they age, generally due to the inactive lifestyle, clothing, extreme summers and minimal outdoor activity that characterises life in Qatar. A similar study in Indonesia found that 78.2% Vit D deficiency was present amongst its elderly population [21].

What is more, with increasing age the capacity of the skin to produce Vit D on sunlight exposure also decreases [23]. Likewise, advanced age reduces Vit D (1,25(OH)2D) production by the kidneys [24]. Accordingly, physiological changes and climate conditions together with advanced age influence Vit D metabolism among the elderly [25]. In the elderly, Vit D deficiency is associated with an increased risk of falls, osteoporosis and fractures [26]. At present, investigation of plasma 25(OH)D is considered as a reliable marker for Vit D level assessment [27, 28, 43].

In our study, considerably more patients from the home-based run services had a Vit D insufficiency as well as severe Vit D deficiency in comparison to the in- and out-patient departments of hospitals (*P* = 0.001). This corroborates reports from western researchers that found a higher occurrence of Vit D insufficiency among communal living elderly [25]. However, in the U.S., Vit D insufficiency was incidentally lower in the elderly except in those patients who sustained hip fracture [25]. Lund et al. [29] found Vit D deficiency in 25% of hip fracture cases, of which 5% had severe Vit D deficiency. However, the incidence of hip fractures in our study (14.9%) was relatively lower compared with earlier studies [29].

The present study observed severe Vit D deficiency in 70% of elderly females. Even though the Qatar demographics showed that the sex ratio for male:female is 1.7:1. The majority of population assigned for this study is female patients; this was decided up on the willingness of participation. Other possible explanation for this might be due to the higher life expectancy in females [21]. Also, Indonesia reported a higher incidence of Vit D deficiency among its elderly females in comparison to elderly males. This high number of women with Vit D deficiency in the Middle East and Asia may be attributed to socio-cultural practices such as the use of the veil outside in the Sun.

Aging has been associated with T2DM [30]. Moreover, several epidemiological studies have found a negative correlation between T2DM, obesity and Vit D deficiency [31–33]. Mathieu et al. advocated Vit D supplementation for improving glucose tolerance in patients with Vit D deficiency [34]. Further, Hidayat et al. [21] reported that in overweight elderly patients, their high BMI was pointedly associated with an increased Vit D deficiency.

**4. Discussion**

82 A Critical Evaluation of Vitamin D - Clinical Overview

geriatric population.

[27, 28, 43].

[41].

It has been suggested that, lifestyle and socio-cultural practices may be related to the high Vit D deficiency reported among the young recently in Qatar [25]. However, the relationship

Unfortunately, there are no accurate figures for the confident determination of vitamin D deficiency in Qatar due to the geographical and/or demographical nature of studies conducted

However, centred on data gathered from a review of the system, about 90% of the Qatari population may be deficient in serum levels of the vitamin. This exclusive study from the region tries to address the impact of age, diabetic status and dyslipidaemia on Vit D deficiency among the

This study found the existence of an extraordinary large number of Vit D deficiency (71.8%) among the elderly in Qatar, which may be attributed to their limited exposure to sunlight as they age, generally due to the inactive lifestyle, clothing, extreme summers and minimal outdoor activity that characterises life in Qatar. A similar study in Indonesia found that 78.2%

What is more, with increasing age the capacity of the skin to produce Vit D on sunlight exposure also decreases [23]. Likewise, advanced age reduces Vit D (1,25(OH)2D) production by the kidneys [24]. Accordingly, physiological changes and climate conditions together with advanced age influence Vit D metabolism among the elderly [25]. In the elderly, Vit D deficiency is associated with an increased risk of falls, osteoporosis and fractures [26]. At present, investigation of plasma 25(OH)D is considered as a reliable marker for Vit D level assessment

In our study, considerably more patients from the home-based run services had a Vit D insufficiency as well as severe Vit D deficiency in comparison to the in- and out-patient departments of hospitals (*P* = 0.001). This corroborates reports from western researchers that found a higher occurrence of Vit D insufficiency among communal living elderly [25]. However, in the U.S., Vit D insufficiency was incidentally lower in the elderly except in those patients who sustained hip fracture [25]. Lund et al. [29] found Vit D deficiency in 25% of hip fracture cases, of which 5% had severe Vit D deficiency. However, the incidence of hip fractures in our study

The present study observed severe Vit D deficiency in 70% of elderly females. Even though the Qatar demographics showed that the sex ratio for male:female is 1.7:1. The majority of population assigned for this study is female patients; this was decided up on the willingness of participation. Other possible explanation for this might be due to the higher life expectancy in females [21]. Also, Indonesia reported a higher incidence of Vit D deficiency among its elderly females in comparison to elderly males. This high number of women with Vit D deficiency in the Middle East and Asia may be attributed to socio-cultural practices such as the

Vit D deficiency was present amongst its elderly population [21].

(14.9%) was relatively lower compared with earlier studies [29].

use of the veil outside in the Sun.

between Vit D deficiency and its impact on the health of the elderly is still lacking.

Our findings previously published online [35] confirm these earlier reports on the link between type 2 diabetes (T2DM), body mass index and Vit D deficiency. In this study, markers of T2DM (raised HbA1c and high fasting blood glucose levels) had a negative association with levels of circulating vitamin D3. It was observed that significantly high levels of blood glucose (*P* < 0.005) and HbA1c (*P* < 0.03) were associated with acute Vit D deficiency. Pittas et al. [36] in a double-blind, randomized, controlled trial reported that in healthy adults with impaired fasting blood glucose, supplementation with vitamin D may attenuate increases in glycaemia and insulin resistance that occur over time.

In addition, well documented also has been the association between low Vit D levels and chronic kidney disease (CKD). Previous research has shown that in a large majority of patients with advanced CKD (stage 2), their levels of Vit D have a tendency to be lower than the normal limit, although in patients with advanced CKD (stage 3 and 4), Vit D levels fell significantly [37, 38]. Furthermore, elderly patients (<65 years) are likely to have an increased association of Vit D deficiency and renal dysfunction with lower glomerular filtration rate (GFR) [39].

The present study showed that eGFR was not associated with Vit D levels. Our findings are consistent with an earlier study showing no association between an impaired eGFR and Vit D deficiency (*P* < 0.432) [40]. Fraser et al. [41] explored the role of serum 25(OH)D, parathyroid hormone and calcium in the development of cardiovascular sicknesses. A positive association was identified between HDL-C and 25(OH) D levels; considerably lower HDL-C levels were detected in patients with acute Vit D deficiency, consistent with the findings of Fraser et al. [41]. As a result, HDL-C levels and Vit D deficiency had a substantial opposite relationship, as patients with lower levels of HDL-C had acute Vit D deficiency. LDL-C and triglyceride were less in patients with acute Vit D deficiency in comparison to those with ideal levels [42].

New research has found in recent times that the presence of vitamin D receptors and the vitamin D activating enzyme (1-hydroxylase) in the brain has advised a possible role of vitamin D in cognitive function. It is suggested that the vitamin D receptor and catalytic enzymes are confined to a small area of the brain involved in complex planning, processing and the creation of new memories. These findings in theory link the role of vitamin D to cognitive impairment, depression and also multiple sclerosis. Although, the current findings cannot be supported as dementia is associated with severely low Vit D levels.

Epidemiological research recently has underlined the significance of Vit D and calcium supplementation for communal living, hospitalized and care home elderly. The vitamin D requirements may vary only based on customary calcium intake. The therapeutic potential of vitamin D will not be affected by age and sex difference but may be affected by ethnicity [44, 45].

Taking into consideration the socio-cultural and hereditary factors predominant in the Middle East, the proper controlling of Vit D deficiency together with metabolic disorders should be made an essential part of treatment for the ageing people. Additionally, the eluding of Vit D deficiency among the elderly may possibly be useful for the optimum managing of high-risk metabolic disorders such as diabetes mellitus and dyslipidaemia which in time will improve the care provided for the population.

This study exposed certain limitations, such as the lack of cause-specific mortality data, as well as details of Vit D supplementation. Another limitation was that the influence of seasons and Vit D deficiency was not considered in the analysis; as the study was retrospective in nature. Even though these limitations exist, the large sample size is representative of the geriatric population in the Middle East. Therefore, this study gives an understanding into the occurrence of Vit D deficiency and its attendant issues among the elderly in Qatar.

In conclusion, vitamin D as a nutrient performs several functions, fundamental to the biological system of the human body including the endocrine and metabolic systems. A large occurrence of Vit D deficiency was detected in the elderly. Vit D serum levels were lower, the wrong way round with HbA1c and HDL-C levels. The follow-up indicated a small but major improvement in Vit D levels after Vit D supplements had been administered. For that reason, further research is required to assess whether or not administering Vit D supplements improves low HDL-C levels and/or glycemic control in T2DM.
