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Prevalence of vitamin D deficiency rickets in adolescent school
girls in Western region, Saudi Arabia
Aisha M. Siddiqui, MRCP (London), FRCP (Edin), Hayat Z. Kamfar, MBBCH, CABP.
441
ABSTRACT
Objectives: To determine the prevalence of vitamin
D deficiency rickets among female adolescents
and assess its relation to calcium intake and sun
exposure.
Methods: Four hundred and thirty-three school
girls between 12-15 years old were selected
randomly from different schools in Jeddah,
between October 2003 - February 2004. We
identified symptoms of rickets and determined
the dietary habits and sun exposure habits, and
laboratory investigations were also carried out,
Results: It was found that, out of 433 cases, 350
(81%) had low vitamin D levels. Approximately
40% had very low levels of vitamin D and 61%
were asymptomatic. Most of the symptoms were
non specific. ere was a positive correlation
between low calcium in the diet and less sun
exposure to low levels of vitamin D. Approximately
96% had normal serum phosphate, 89% had
normal serum calcium, and 40% had normal
serum alkaline phosphatase levels.
Conclusion: Vitamin D deficiency is common
among adolescent females in Jeddah, Saudi Arabia.
Cases are missed due to lack of symptoms in most
cases and normal bone chemistry. Serum vitamin
D level should be carried out in suspected cases.
Health and nutritional education should be
encouraged in schools. Focusing on the importance
of adequate milk intake and sun exposure should
be given a priority in any health education
program.
Saudi Med J 2007; Vol. 28 (3): 441-444
From the Department of Medicine (Siddiqui) and the Department
of Pediatrics (Kamfar), King Abdulaziz University Hospital,
Jeddah, Kingdom of Saudi Arabia.
Received 21st June 2006. Accepted 4th November 2006.
Address correspondence and reprint request to: Dr. Aisha
M. Siddiqui, Associate Professor, Department of Medicine,
King Abdulaziz University Hospital, PO Box 80215, Jeddah
21589, Kingdom of Saudi Arabia. Fax. +966 (2) 6408315.
E-mail: medconf@yahoo.com
V
itamin D metabolites are important for the normal
development of bone and the metabolism of its
constituent ions. Deficiency or abnormal metabolism of
vitamin D is often responsible for rickets. ere is little
vitamin D in the ordinary diet and the major source of
vitamin D is the vitamin D
3
synthesized in the skin
when it is exposed to ultraviolet light.
1
Growing age
groups (children and adolescents) are in a critical period
for skeletal mass accretion,
2-3
where adequate sun exposure
is needed. Female adolescents may be more vulnerable
especially Asians, as it was found in many countries that
Asian females have low levels of vitamin D.
4-11
In Saudi Arabia, many studies were carried out to study
Osteomalacia and Rickets in different age groups and
both sexes, but recently, only few studies were conducted
on healthy adult females,
12-14
and few on symptomatic
adolescents with rickets.
15-18
Some data are available on
vitamin D status in adolescents carried out in 1992,
7,8
but since then, no further studies have been carried out to
assess the prevalence of vitamin D deficiency in adolescent
females, although there is an impression from clinical
practice that it is not uncommon. e aim of our study
is to screen adolescent school girls aged 12-15 years, in
which a physiological growth spurt occurs and vitamin D
deficiency can occur quickly and asymptomatically. is
study looks into the prevalence of vitamin D deficiency
rickets among this group in Jeddah City of Saudi Arabia,
studies the symptoms and blood bone chemistry, and
identifies causative factors by reviewing the dietary habits
and sun exposure.
Methods. is research was funded by King Abdulaziz
University, Jeddah. e collection of the data and blood
samples took place between October 2003 – February
2004. Six hundred female students aged 12-15 years were
randomly selected from 6 schools chosen from different
areas of Jeddah and the questionnaires were distributed to
them, which reviewed the dietary habits, dairy products
consumption, exposure to sun, and presence or absence
of any symptoms. Four hundred and thirty-three students
were included in the study, who had no history of renal,
hepatic diseases, or malabsorption, no family history of
442
Vitamin D deficiency in school ... Siddiqui & Kamfar
Saudi Med J 2007; Vol. 28 (3) www.smj.org.sa
rickets, and were not on anti-convulsant therapy or
vitamin supplementations. Laboratory investigations
included blood bone chemistry (calcium, phosphate,
and alkaline phosphatase), parathyroid hormone assay,
and serum concentration of 25-hydroxycolcalciferol
(25-OHD), which was measured using enzyme-linked
immunosorbent assay (ELISA) technique (K2110,
Immunodiagnostic [Dutch Company], Holland).
Symptomatic vitamin D deficiency rickets was defined
by the presence of muscle, bone or back pain, muscle
spasms, or twitches in addition to serum (25-OHD)
concentrations of <25 nmol/L (n=25-125 nmol/L).
Asymptomatic vitamin D deficiency rickets was defined
by the presence of serum 25-OHD concentrations
of <25 nmol/L, with no symptoms. Severe vitamin
D deficiency was defined by the presence of serum
25-OHD concentrations of <12.5 nmol/L.
Statistical analysis was carried out using Statistical
Package for Social Sciences (SPSS) version 10. Chi
square test was used to analyze group differences for
categorical variables. For continuous variables, t-test
was used. P value of <0.05 was considered significant.
Results. Out of 433 girls, 350 (81%) had low
vitamin D levels, ranging from 2.2-24.0 nmol/L.
Approximately 194 girls were Saudi by birth (56%).
Two hundred thirteen girls were asymptomatic (61%).
Back pain was the most common complaint as
shown in Table 1. A severe vitamin D deficiency was
noticed in 173 (40%) girls of the total population
studied. e intake habits of dairy products in the
low vitamin D girls, showed that only 125 (36%) had
daily consumption versus 170 (48%) who rarely had
any, and that was statistically significant with p value of
0.013. Out of 150, only 31 (21%) took near the daily
requirement of milk such as >3 cups or equivalent of
milk products, but that was not statistically significant
with p value of 0.13 due to the girls who answered this
part of the questionnaire were few. e sun exposure
habits in the low vitamin D, girls showed that 67 (19%)
were never exposed to sun, 205 (67%) were exposed
in less than 15 minutes, and 235 (75%) had indirect
exposure. at was statistically significant with p values
of 0.013, 0.041, and 0.007.
Cases with a severe vitamin D deficiency (very
low vitamin D levels) were significantly more prevalent
with lower income and with rare sun exposure
[p=0.015 (Table 2)] and [p=0.01 (Table 3)]. Table 4
shows number of rachitic girls who had low calcium
and phosphate and high alkaline phosphatase and
parathormone levels. It was noticed that the severity
of vitamin D deficiency had no relation to the serum
levels of calcium, phosphate, and alkaline phosphatase,
but was inversely related to the parathormone levels
Table 1 - Prevalence of symptoms in 350 girls with rickets.
Symptoms n (%)
Back pain
Bone pain
Twitches
Muscle pain
Cramps
92 (26)
50 (14)
15 (4)
13 (4)
11 (3)
Table 2 - Relation of very low vitamin D level (<12.5 nmol/L) to the
family income.
Income
(Saudi Riyals)
Vitamin D level
above 12.5 nmol/L
n (%)
Vitamin D level
below 12.5 nmol/L
n (%)
Total
n (%)
3000
3000 – 8000
>8000
Total
40 (37)
42 (53)
57 (56)
139 (48)
67 (63)
38 (47)
44 (44)
149 (52)
107 (37)
80 (28)
101 (35)
288 (100)
P = 0.015
Table 3 - Relation of very low vitamin D level (<12.5 nmol/L) to sun
exposure.
Sun
exposure
Vitamin D level
above 12.5 nmol/L
n (%)
Vitamin D level
below 12.5 nmol/L
n (%)
Total
n (%)
Daily
Never
Total
129 (55)
24 (37)
153 (51)
104 (45)
43 (63)
147 (49)
233 (78)
67 (22)
300 (100)
P = 0.01
Table 4 -
Abnormal biochemical values of the 350 rachitic girls.
Normal value n (%)
High alkaline phosphatase (0 - 250 u/l)
High parathormone (1.6 – 6.5 pmol/l)
Low calcium (2.1 – 2.6 mmol/l)
Low phosphate (0.81 – 1.58 mmol/l)
211 (60)
149 (43)
39 (11)
14 (4)
Table 5 - Intake of dairy products in symptomatic and asymptomatic
girls with rickets.
Intake
Symptomatic
n (%)
Asymptomatic
n (%)
Total
n (%)
Daily
Twice/week
Rarely
Total
45 (36)
14 (26)
78 (45)
137 (39)
80 (64)
41 (74)
92 (55)
213 (61)
125 (36)
55 (16)
170 (48)
350 (100)
P = 0.024
443
www. smj.org.sa Saudi Med J 2007; Vol. 28 (3)
Vitamin D deficiency in school ... Siddiqui & Kamfar
time, it is alarming as many cases of rickets could be
missed if 25-OHD was not measured, especially that
alkaline phosphatase levels were also normal in many
cases. e presence of normal calcium levels in vitamin
D deficient patients were also observed by Sedrani
32
in Saudi Arabia. e presence of compensatory high
parathormone levels could contribute to normal serum
calcium levels, which were observed in our study. An
adolescent period is important in female life. Good
nutrition to maintain calcium and vitamin D stores, and
enough sun exposure is important for bone formation
and prevention of osteomalacia/rickets. Adolescent
rickets if not diagnosed, can progress to osteomalacia in
adulthood and during pregnancy with probably serious
consequences to both mother and the baby. ere is
also high risk of postmenopausal osteoporosis in these
girls.
35
In conclusion, vitamin D deficiency has a high
prevalence in adolescent females in Jeddah area and
probably in Saudi Arabia in general. Most of the cases
are asymptomatic and if present, symptoms are non
specific. is high prevalence of vitamin D deficiency
is attributed to both lack of dietary dairy intake and to
lack of sun exposure. Many cases of adolescent rickets
are undiagnosed and we urge physicians to have a
higher degree of clinical suspicion for hypovitaminosis
D and to screen all the patients with non specific
musculoskeletal pain by measuring 25-OHD. We
also recommend improved dietary supplies of highly
bioavailable calcium (such as milk) and vitamin
D from food fortification, the improvement of sun
exposure facilities in schools and the integration of the
topic of vitamin D deficiency, and osteomalacia/rickets
into the school syllabus in order to improve the
health education of the students and the population
as a whole. Furthermore, screening studies are needed
in different regions of Saudi Arabia to assess the
magnitude of this preventable problem.
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