Perceptions of Dietary Factors Promoting and Preventing Kidney Stones Among Taif City Population - A Cross-Sectional Study.

Background and Aim: Renal stones are the most common urological disorder resulting in different marked morbidities with different risk factors. This study aimed to assess the perceptions of the general population regarding dietary factors in promoting and preventing nephrolithiasis in the Taif region.
Methods: We carried out this cross-sectional study during a period of 4 months. All Taif city population who were ≥18 years old were included in the study regardless of their gender and history of urolithiasis. Participants were excluded if they were <18 years of age, not Taif city residents, and whose primary language was not Arabic. Data were analyzed using SPSS ver. 23.
Results: It was found that 68.4% of the participants had poor knowledge of dietary risk factors. Further, 86.4% of the participants thought that their diet could affect the risk of kidney stone formation, and 88.6% believed that water can decrease the risk of kidney stone formation. In addition, 54.5% and 66.3% knew that increased consumption of meat and smoking can increase the risk of kidney stone formation.
Conclusion: The knowledge regarding specific dietary risk factors promoting and preventing kidney stones formation was poor among the Taif city population. Copyright:

INTRODUCTION

Kidney stones are among the most common urological diseases, dramatically affecting health and quality of life in any population worldwide. They can cause considerable morbidity, including flank pain, urinary tract infection (UTI) and inflammation, hydronephrosis (swelling of one or both kidneys), and decreased renal function.[1] The prevalence varies by age and gender. The peak age in men is 30 years; women have a bimodal age distribution, with peaks at 35 and 55 years with a prevalence rate of approximately 1.7%–8.8% worldwide.[2] Approximately 7% of women and 13% of men develop a kidney stone during their lifetime. A higher incidence of stone formation is noted in areas of hot weather than moderate ones.[3] Some factors lead to an increase in the risk of stones formation, such as low fluid intake, increased perspiration, and increased urinary concentration together with climatic conditions and other factors such as genetic factors, nutritional habits, water hardness, race, sex, age, occupation, and body mass.[4] Lifestyle can add more risk of stone formation as overweight individuals and obese individuals were the most susceptible to develop idiopathic calcium oxalate deposition in their kidneys, which may progress into renal stone formation.[5] Several dietary factors are significant contributors to the high incidence of nephrolithiasis, precisely a diet low in fiber and a high in animal protein, fat, and sodium.[6]

Nowadays, significant evidence suggests that NaCl may lead to idiopathic calcium nephrolithiasis formation and recurrence of stones as higher sodium chloride intake has been linked with hypercalciuria and hypocitraturia; both are major risks factors for calcium stone formation.[7] The most significant constituent of kidney stones is calcium oxalate. Ascorbic acid (vitamin C) is an essential nutrient acting as a cofactor in several enzymatic pathways derived from fresh fruits and vegetables. Ingested vitamin C is partly converted to oxalate and then excreted in the urine, potentially increasing the risk of calcium oxalate stone formation.[8]

Kidney stones are a widespread problem, especially in Saudi Arabia. Creating awareness educating the public about the risk factors of the development of kidney stones would help reduce the public health burden of urinary stone disease. Unfortunately, there is a lack of studies examining the public's knowledge and perceptions about kidney stones in the Taif region. Thus, this study aimed to assess the general population's perceptions regarding dietary factors in promoting and preventing nephrolithiasis in the Taif region.

METHODOLOGY

This is a cross-sectional study carried out over 4 months. The ethical committee of health affairs of Taif city approved this study. To confirm participants' willingness to fill the survey voluntarily, a yes-no question had to be answered before completing the questionnaire. Inclusion criteria were Taif city residents who were ≥18 years old regardless of gender and regardless of whether they have urolithiasis history. Participants who were <18 years of age, those who were not Taif city residents, and whose primary language was not Arabic were excluded.

Information was collected from 1070 participants by using a 22-question, pretested online questionnaire. The information included sociodemographic details (e.g., sex, age, level of education, 12-month income, and marital status), and previous history of chronic conditions (e.g., diabetes mellitus, hypertension, dyslipidemia, heart diseases, renal diseases, asthma, or other respiratory diseases and other medical conditions). If a history of kidney stones was present, further details regarding the number of stones and whether the patient received a preventive educational program were collected. Other parts of the questionnaire focused on evaluating participants' awareness about dietary risk factors of nephrolithiasis.

Data analysis was carried out using Statistical Package for Social Sciences ver. 23. (SPSS Inc., Chicago, IL, USA). Qualitative data were expressed as numbers and percentages, and a Chi-squared test (χ2) was applied to assess the relationship between variables. Quantitative data were expressed as mean and standard deviation (mean ± SD), and P < 0.05 was considered statistically significant.

RESULTS

The sociodemographic characteristics of the participants showed that 72% were females, 57.4% had an age range of 18–28 years, 64.9% were graduates, and 35.2% had a yearly household income of <10,000 riyals. It was found that 8.5% of the participants had kidney stones, among which 4% had 1–2 stones; 4.6% had information on preventing getting kidney stones again, and 3.2% had this information from a family doctor.

The majority of the participants (86.4%) correctly thought that the food they eat or the beverages they drink affect the risk of kidney stone formation; 88.6% knew that water decreases the risk of kidney stone formation. Most of them (80.4%) knew that salt increases the risk of kidney stone formation; 54.5% thought that increased consumption of beef, veal, fish, and chicken increase the risk of urolithiasis. Only 16% knew that some fruits/vegetables increase the risk of kidney stone formation. Most of the participants (66.3%) knew that smoking increases the risk of forming kidney stones; 14% knew that they should limit the intake of dairy foods (milk, yogurt, and cheese), 34.1% knew that eating nuts increase their risk of forming kidney stones, and 65.9% knew that they would be at a greater risk for developing kidney stones if they overeat. The most known drink that is thought to increase the risk of developing kidney stones was beer (66.1%) [Table 1].

Table 1

Participants’ responses regarding factors that affect kidney stone formation

Questions	n (%)
Think that the foods they eat, or drink can affect the risk of kidney stone formation
Yes (correct)	940 (86.4)
No	37 (3.4)
I do not know	111 (10.2)
How does the amount of water you drink affect your risk of forming kidney stones?
Water does not affect the risk of kidney stone formation	68 (6.3)
Water increases the risk of kidney stone formation	56 (5.1)
Water decreases the risk of kidney stone formation (correct)	964 (88.6)
If you drink a lot of water early in the day, then you don’t need to drink any water in the evening
Yes	40 (3.7)
No (correct)	986 (90.6)
I don’t know	62 (5.7)
How does the amount of salt you eat affect your risk of forming kidney stones?
Salt does not affect the risk of kidney stone formation	178 (16.4)
Salt increases the risk of kidney stone formation (correct)	875 (80.4)
Salt decreases the risk of kidney stone formation	35 (3.2)
How does the amount of meat (beef, pork, and veal), fish, and chicken you eat affect your risk of forming kidney stones?
	432 (39.7)
These foods do not affect the risk of kidney stone formation	593 (54.5)
These foods increase the risk of kidney stone formation (correct)	63 (5.8)
These foods decrease the risk of kidney stone formation
Can eating certain fruits and vegetables affect your risk of forming kidney stones?
Fruits/vegetables do not affect my risk of kidney stones	521 (47.9)
Some fruits/vegetables increase the risk of kidney stone formation (correct)	174 (16)
Some fruits/vegetables decrease the risk of kidney stone formation	393 (36.1)
How does smoking affect your risk of forming kidney stones?
Smoking has no effect on forming kidney stones	357 (32.8)
Smoking increases the risk of forming kidney stones (correct)	721 (66.3)
Smoking decreases the risk of forming kidney stones	10 (0.9)
Which of the following drinks increases the risk of forming kidney stones?
Beer	719 (66.1)
Tea (correct)	143 (13.2)
Coffee	473 (43.5)
Water	257 (23.7)
Alcohol	635 (58.4)
Soda	356 (32.8)
Fruit	404 (37.2)
Juice	366 (33.7)
Lemonade	516 (47.5)
Can drinking milk or eating yogurt or cheese affect your risk of forming kidney stones?
Yes, I should limit my intake of these products. (correct)	152 (14)
No, I should try to eat or drink some of these foods daily	298 (27.4)
I don’t know	638 (58.6)
Can eating nuts affect your risk of forming kidney stones?
Yes, they increase my risk (correct)	371 (34.1)
No, they don’t increase my risk	254 (23.3)
I don’t know	463 (42.6)
Which of the following puts you at a higher risk of forming kidney stones?
If I overeat I am at a greater risk for forming kidney stones (correct)	717 (65.9)
If I am careful not to overeat that may decrease my risks of forming kidney stones	371 (3.41)

For the 11 knowledge items, a score of 1 was given for the correct answer, and a score of 0 was given for any wrong answer, leaving a total score ranging from 0 to 11. Participants who got <50% of the total score were classified as having poor knowledge and those who got 50%–75% were classified as having fair knowledge. Those who got >75% were classified as having good knowledge. The mean knowledge score was 4.78 ± 1.47, and the prevalence of poor, fair, and good level of knowledge among the participants was 68.4%, 30.8%, and 0.8%, respectively. As for the participants' attitude, most of them (68.7%) agreed that they are willing to change the way they eat or drink to lower the risk of urolithiasis. The male participants and those who had a yearly income of 41,000–60,000 SAR constituted a significantly higher percentage of those who had a good level of knowledge regarding kidney stones (P < 0.05) Participants who had a kidney disorder constituted a significantly higher percentage of those who had a good level of knowledge regarding kidney stones (P < 0.05). Participants who had 1–2 kidney stones and did not get information on preventing kidney stones recurrence constituted a significantly higher percentage of those who had a good level of knowledge regarding kidney stones (P < 0.05) [Table 2].

Table 2

Relationship between participants’ knowledge about kidney stones and their characters

Variable	Knowledge level			χ 2	P
	Poor n (%)	Fair n (%)	Good n (%)
Gender
Male	180 (59)	121 (39.7)	4 (1.3)	17.49	<0.001
Female	564 (92)	214 (27.3)	5 (0.6)
Age (years)
18-28	425 (68.1)	194 (31.1)	5 (0.8)	7.13	0.308
29-39	128 (74.9)	40 (23.4)	3 (1.8)
40-59 60-79	178 (64.7) 12 (66.7)	94 (34.2) 6 (33.3)	3 (1.1) 0 (0.0)
Highest school completed
Primary/elementary	10 (90.9)	1 (9.1)	0 (0.0)	3.16	0.408
High school	34 (77.3)	9 (20.5)	1 (2.3)
College/university	220 (67.3)	104 (31.8)	3 (0.9)
Graduate school	480 (68)	221 (31.3)	5 (0.7)
Yearly household income (Saudi riyals)
<10,000	288 (75.2)	94 (24.5)	1 (0.3)	41.01	< 0.001
10,000-25,000	310 (69)	136 (30.3)	3 (0.7)
26,000-40,000	63 (70)	25 (27.8)	2 (2.2)
41,000-60,000	34 (53.1)	28 (4.8)	2 (3.1)
61,000-80,000	49 (48)	52 (51)	1 (1)
Marriage status
Single	393 (67.9)	181 (31.3)	5 (0.9)	0.6	0.996
Married	230 (68.8)	141 (30.3)	4 (0.9)
Divorced	18 (72)	7 (28)	0 (0.0)
Widowed	13 (68.4)	6 (31.6)	0 (0.0)
Chronic diseases
Yes	283 (69.2)	122 (29.8)	4 (1)	0.24	0.884
No	460 (67.6)	212 (31.2)	7 (1)
Kidney disorder
Yes	25 (53.2)	20 (42.6)	2 (4.3)	9	0.011
No	718 (69)	314 (30.2)	9 (0.9)
History of kidney stone
Yes	55 (61.1)	32 (35.6)	3 (3.3)	7.01	0.135
No	626 (69.2)	272 (30.1)	7 (0.8)
I do not know	62 (66.7)	30 (32.3)	1 (1.1)
Number of kidney stones (n=90)
1-2	31 (72.1)	10 (23.3)	2 (4.7)	32.26	<0.001
3	10 (38.5)	16 (61.5)	0 (0.0)
4	4 (40)	5 (50)	1 (10)
5-6	6 (100)	0 (0.0)	0 (0.0)
>6	4 (80)	1 (20)	0 (0.0)
Got information for prevention of kidney stones (n=90)
Yes	27 (54)	23 (46)	0 (0.0)	30.48	<0.001
No	21 (67.7)	7 (22.6)	3 (9.7)
I don’t remember	7 (77.8)	2 (22.2)	0 (0.0)
Source of information about kidney stones (n=50)
Urologist	4 (80)	1 (20)	0 (0.0)	10.03	0.123
Family Doctor	16 (45.7)	19 (54.3)	0 (0.0)
Dietician	7 (70)	3 (30)	0 (0.0)

DISCUSSION

The reported prevalence of nephrolithiasis in this study was 8.5%, which is very high compared to the global prevalence.[910] A recent study conducted in Saudi Arabia has reported a prevalence of 9.1% among the adult population.[11] Another study done in the Western province of Saudi Arabia had reported a prevalence of 6.2%, which also showed more prevalence among adult males.[12] Therefore, prevention of kidney stone formation is crucial in reducing the economic and health burden, and preventive programs should aim at minimizing the modifiable risk factors. The findings of this study showed that the knowledge regarding the relationship of diet with nephrolithiasis was not satisfactory among the study population. Poor knowledge regarding dietary factors and their relationship with nephrolithiasis incidence can act as a big hurdle for its prevention and risk reduction. Improving disease knowledge contributes to an increased awareness of the disease causation and its preventive measures, which would help them give up unhealthy diet and lifestyle practices.[13] It is also reported that prior education regarding the knowledge of dietary risk for nephrolithiasis will be maintained, and this can help reduce the incidence of the disease.[14]

Overall, the prevalence of nephrolithiasis was reported to be significantly higher in men than in women in the majority of the studies done in the Kingdom.[1112] This may be one of the reasons why our findings showed higher knowledge and awareness among males. Calcium nephrolithiasis is the most common form of nephrolithiasis and accounts for 75% of all phenotypes of renal stones.[15] Calcium is an essential element for the proper functioning of bones and muscles, and its serum level is tined by the kidney and other organs in the body.[16] Reducing the intake of foods that are rich in calcium, such as dairy products (yogurt, milk, cheese), fish (sardines, salmon), sulfate-containing vegetables (tofu, turnip greens, kale, bok choy, broccoli), and vegetables rich in oxalate (soybeans, spinach, white beans, almonds) is an appropriate therapeutic strategy to decrease the incidence of calcium nephrolithiasis.[1718] Fluid intake is another important risk factor in the incidence of kidney stones.[19] Drinks containing a high amount of fructose, such as carbonated and sugar-added soft drinks, are more popular in Saudi Arabia, which is found to increase the excretion of calcium, oxalate, and uric acid, thereby increasing the risk of nephrolithiasis.[2021] It is reported that fruit juice, grapefruit, and apple juices do not increase the risk of renal stones, whereas consumption of orange juice is found to reduce the risk of nephrolithiasis by 12%.[2223] Kang et al.[24] had demonstrated that long-term intake of lemonade reduced the risk of renal stone formation in patients with hypocitraturic nephrolithiasis. The current study findings showed that 80.4% of the participants were aware that increased consumption of common salt (NaCl) increases the risk of nephrolithiasis, which is supported by the other studies evidence that showed increase consumption of salt is associated with nephrolithiasis.[2526] Studies show that increased consumption of animal protein such as red meat, fish, and chicken increases the serum and uric acid levels in the body, which in turn increases the susceptibility of renal stone formation.[222728] Smoking is another risk factor for the development of renal stones,[2930] and approximately 66% of the participants agreed to this.

Dietary recommendations should highlight the necessity of reducing consumption of food rich in calcium, oxalates, sugar, salt, and red meat, and people should be encouraged to improve their lifestyle practices. Our study followed an observational design that could have been subjected to confounding. Second, the study findings were based on self-reported answers; this may have called upon social desirability bias or recall bias. A mixture of convenience and snowball sampling using an online survey method was used to collect responses; this could have affected the generalizability of the findings. However, considering the COVID-19 situation, and an easier and faster technique to assess the knowledge and awareness related to diet and its relationship with nephrolithiasis, an online survey is proved to be the most suitable.[31] Despite these limitations, this is one of the largest studies that collected responses from Taif city residents with a good response rate, which may have shown some degree of representativeness. Therefore, these findings can provide new insights into opportunities for educating the public regarding the importance of diet in nephrolithiasis.

CONCLUSION

In conclusion, the knowledge regarding specific dietary risk factors of developing kidney stones was poor among the Taif city population. However, most of the participants were found to be aware of the fact that their diet can affect the risk of kidney stones. Therefore, health education programs through different media platforms should be imparted, which should concentrate on the importance of dietary consideration for high-risk groups and other modifiable risk factors such as smoking and sedentary lifestyles.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.