Association of Dietary Calcium Intake with Dental, Skeletal and Non-Skeletal Fluorosis among Women in the Ethiopian Rift Valley

Abstract

Fluorosis is a major public health problem in the Rift Valley of Ethiopia. Low calcium (Ca) intake may worsen fluorosis symptoms. We assessed the occurrence of fluorosis symptoms among women living in high-fluoride (F) communities in South Ethiopia and their associations with dietary Ca intake. Women (n = 270) from two villages provided clinical and questionnaire data. Dental fluorosis examination was done using Dean’s Index, and skeletal and non-skeletal fluorosis assessment was carried out using physical tests and clinical symptoms. Daily Ca intake was estimated by a food frequency questionnaire. Food, drinking water and beverage samples were analyzed for F level. Many subjects (56.3%) exhibited dental fluorosis. One-third of the women were unable to perform the physical exercises indicative of skeletal fluorosis; about half had ≥2 symptoms of skeletal/non-skeletal fluorosis. The average F level in drinking water sources was ~5 mg/L. The F content in staple food samples varied from 0.8–13.6 mg/kg. Average Ca intake was 406 ± 97 mg/day. Women having ≤400 mg/day Ca intake had ~3 times greater odds of developing skeletal rigidity with joint pains [AOR = 2.8, 95%CI: 1.6, 5.0] and muscular weakness [AOR = 2.9, 95%CI: 1.3, 6.3] compared to those with higher intakes. No association of calcium intake was seen with dental fluorosis. As low dietary Ca intake was associated with symptoms related to skeletal and non-skeletal fluorosis, this warrants nutritional intervention on calcium intakes in this setting.

Prevalence of Skeletal Fluorosis in Northern Tanzania: A Follow-Up Study

“…This finding makes logical sense, as with increasing age, the individual has been exposed to high fluoride consumed in drinking water for a longer period of time and is in keeping with other studies. 20,22,28 Previous studies identify estrogen as a protective factor for SF, 11 with lower rates of SF seen in females. 11,24 This study found no significant difference between sexes.…”

“…It has been shown that increased dietary calcium may mitigate the severity of SF, and it is important to consider promoting high-calcium foods or supplements that are cost-effective and sustainable, such as calcium-containing eggshell powder supplementation, which has been tested in Ethiopia. 22,28,34 A major advantage of this study is the large sample size. The reliability of the demographic data is strengthened by the comparison of results from the recent census within this established demographic surveillance site.…”

“…This finding makes logical sense, as with increasing age, the individual has been exposed to high fluoride consumed in drinking water for a longer period of time and is in keeping with other studies. 20 , 22 , 28 …”

“…However, the full effects of these variables on the pathogenesis of the disease are still unknown. Recent research from Ethiopia supports the premise that low dietary calcium intake is significantly associated with SF among women 22 , 34 and school-aged children. 28 …”

“…1,3,8,21 Intake over 10 mg/L is linked to crippling SF, 1 associated with profound immobility. 3,16 SF is characterized by a combination of osteosclerosis, osteoporosis, osteomalacia, exostosis, 7,11,18,22 calcification of ligaments and tendons, and extreme bone deformity. 1 The cervical and lumbar vertebrae and major joints of the extremities 11 are most severely affected and can lead to pathological fractures.…”