High prevalence of vitamin D deficiency among children aged 1 month to 16 years in Hangzhou, China

Zhiwei Zhu, Jianying Zhan, Jie Shao, Weijun Chen, Liqin Chen, Wenhao Li, Chai Ji and Zhengyan Zhao
BMC Public Health 2012, 12:126 doi:10.1186/1471-2458-12-126, Published: 14 February 2012

Background: Recent studies have suggested that vitamin D deficiency in children is widespread. But the vitamin D status of Chinese children is seldom investigated. The objective of the present study was to survey the serum levels of 25-hydroxyvitamin D 25(OH)D in more than 6,000 children aged 1 month to 16 years in Hangzhou (latitude: 30degreesN), the capital of Zhejiang Province, southeast China.

Methods: The children aged 1 month to 16 years who came to the child health care department of our hospital, the children's hospital affiliated to Zhejiang university school of medicine, for health examination were taken blood for 25(OH) D measurement. Serum 25(OH) D levels were determined by direct enzyme-linked immunosorbent assay and categorized as <25, <50, and <75 nmol/L.

Results A total of 6,008 children aged 1 month to 16 years participated in this cross-sectional study. All the subjects were divided into subgroups according to their age: 0-1y, 2-5y, 6-11y and 12-16y representing infancy, preschool, school age and adolescence stages respectively. The highest mean level of serum 25(OH)D was found in the 0-1y stage (99 nmol/L) and the lowest one was found in 12-16y stage (52 nmol/L). Accordingly, the prevalence of serum 25(OH)D levels of <75 nmol/L and <50 nmol/L were at the lowest among infants (33.6% and 5.4% respectively) and rose to the highest among adolescents (89.6% and 46.4% respectively). The mean levels of serum 25(OH)D and the prevalence of vitamin D deficiency changed according to seasons. In winter and spring, more than 50% percent of school age children and adolescents had a 25(OH)D level at <50 nmol/L. If the threshold is changed to <75 nmol/L, all of the adolescents (100% percent) had low 25(OH)D levels in winter and 93.7% school age children as well.

Conclusions The prevalence of vitamin D deficiency and insufficiency among children in Hangzhou Zhejiang province is high, especially among children aged 6-16 years. We suggest that the recommendation for vitamin D supplementation in Chinese children should be extended to adolescence.

PDF is attached at the bottom of this page

Less than 20 nanograms/ml of vitamin D

Less than 30 nanograms/ml of vitamin D

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

The UK, much further from equator, has a similar problem vs age

Note: the UK data is % deficiency of 10 nanograms of vitamin D, which is even less than the Chinese 20 nanograms of vitamin D

See also Vitamin D Life

• 2000 IU vitamin D not enough to get most Chinese to 20 ng level – RCT Feb 2015
• Beijing extremely vitamin D deficient even in the fall: 10 ng – April 2013
• Low D in developing countries – less than 5 ng in some children in China – Oct 2010
• Hypothesis – China air conditioning disease is the result of less vitamin D – March 2011
• Rickets in 30 percent of infants in India who had low vitamin D – March 2011
• 76 percent of young adults in western India had less than 20 ng of vitamin D – Aug 2011
• 70 percent of Koreans in their twenties had less than 20ng of vitamin D – Dec 2010
• Overview Deficiency of vitamin D
• All items: Deficiency of Vitamin D 363 items
• Doubling of people less than 30 ng of vitamin D - 75% of whites and 90% of blacks – Feb 2010
• Red Alert – 30% of pre-teens in Tehran had less than 5 ng of vitamin D – Feb 2011
• Every hour of TV watched reduces your lifespan by 22 minutes – Aug 2011 probably the same for multi-media
• 90 % of young health care professionals had less than 30 ng of vitamin D – Nov 2011 probably indoors too much lat 47 degrees
• Teens increasingly indoors has the following graphs