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research letter

Indian Pediatr 2016;53: 434-435

Association of Dietary Calcium Intake and Body Fat with Hypertension in Indian Adolescents

 

Neha A Kajale, #Zulf Mughal, Vaman Khadilkar, Shashi A Chiplonkar and *Anuradha Khadilkar

From Hirabai Cowasji Jehangir Medical Research Institute, Jehangir Hospital, Pune. Maharashtra, India; and #Department of Paediatric Medicine, Royal Manchester Children’s Hospital, Manchester,UK.
Email: [email protected]

  


To explore association of dietary-calcium intake and body-composition with blood-pressure, 417 apparently healthy adolescents (218 boys) were studied for anthropometry, blood pressure, body composition and nutrient intakes using standard protocols. Blood pressure correlated negatively with dietary calcium (r= -0.120, P<0.01) and positively with body fat (r=0.56,P<0.001). Low dietary-calcium intakes and high adiposity may increase risk of hypertension in Indian adolescents.

Keywords: Adiposity, Body composition, Nutrients.



Low dietary calcium intakes are related to conditions other than bone health, such as hypertension, with possible involvement of renin-angiotensin system [1]. Objective of this study was to explore association of dietary calcium intake and body composition with blood pressure (BP) in 10 -14 year-old Indian adolescents.

Four hundred and seventeen apparently healthy adolescents [218 boys , mean (SD) age 12.0 (1.3) years] were enrolled from schools catering to affluent classes from Pune after institutional ethics approval and appropriate consents. Standing height, weight, waist, blood pressure were measured. Body mass index (BMI) and Z scores were computed using standard procedures and reference values. Body composition (body fat% and muscle mass) were measured using Tanita-SC-240, Tetra polar bioelectrical impendence analyzer (Tanita Corporation, Tokyo, Japan) with children wearing minimal clothings, using standard protocol [2]. Three non-consecutive day 24 hour-diet recalls (including one Sunday) were recorded using standardized questionnaires, and nutrient data were analysed using cooked [3] and raw food data base [4].

Prevalence of hypertension (BP >95th centile) was more in boys (7%) than in girls (5%) [5]. Children with pre-hypertension (BP between 85th and 95th centile) and hypertension had significantly higher weight and BMI Z-scores, waist circumference (WC), fat% and lower percent muscle mass (P<0.05) than children with normal BP. One-fourth of the children were overweight and more than 10% were obese. Majority of micronutrients (mineral and vitamins) intakes were lower than recommended daily allowance (RDA) for corresponding age group. Calcium intakes were significantly lower in group with hyper-tension (P<0.05) than normal BP groups. Eight percent of children from hypertension group had daily calcium intakes below RDA as against 58% children with normal BP. Only 20% of all children satisfied RDA for dietary calcium. Dietary calcium intakes negatively correlated with BP (r=-0.120, P<0.01) (unadjusted and after adjusting for energy intake). BP was positively correlated with BMI (r=0.54), WC (r=0.52) and body fat percent (r=0.56) (P<0.001). Generalized linear model analysis revealed that BP was positively associated with body fat % (b=0.48, P= 0.001) and WC (b=0.32, P=0.001) and negatively associated with dietary calcium (b=0.02, P<0.0001) after adjustment for height.

Higher prevalence of hypertension along with higher adiposity has also been reported in previous studies [6]. Lower consumption of calcium has also been reported earlier in adolescents [7]. Beneficial effects of increased calcium intakes/supplementation with calcium on BP have also been reported [8,9]. Mushengezi, et al. [10] reported higher BMI and WC as predictor of mean arterial pressure (MAP), whereas our results indicate that body fat% and WC were predictors of BP.

In conclusion, low dietary calcium intakes and high adiposity contribute to risk of hypertension in Indian adolescents. Thus, meeting RDA for calcium seems to be critical not only for bone health but also for prevention of hypertension, especially in presence of adiposity.

Acknowledgements: Director, HCJMRI, Dr. Uma Divate for giving permission for carrying out this study.

Contributors: NAK, ZM, VVK, SAC and AVK: designed research; NAK, AVK were involved in data collection; All authors were involved in data analysis and manuscript writing; AVK has primary responsibility for final content. All authors read and approved the final manuscript.

Funding: Corporate Social Grant: Novo Nordisk India Pvt. Limited; Competing interests: None stated.

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