Researchers looked at how many people in China didn’t get enough vitamin A from 1990 to 2021, and the news is encouraging. They found that vitamin A deficiency has been dropping significantly over the past 30 years, with cases falling by about 5% each year. The study also predicts that this improvement will continue through 2050, though children and women still need special attention. This research shows that public health efforts to improve nutrition are working, but there’s still more to do to make sure everyone gets the vitamins they need.

The Quick Take

  • What they studied: How common vitamin A deficiency is in China and whether it’s getting better or worse over time, plus predictions for the next 25 years
  • Who participated: This wasn’t a traditional study with volunteers. Instead, researchers analyzed health data collected across China from 1990 to 2021, looking at information about millions of people to understand national trends
  • Key finding: Vitamin A deficiency cases dropped by about 5% every year from 1990 to 2021, and this improvement is expected to continue, though more slowly, through 2050. Girls and women are affected more than boys and men, and children have higher rates than adults
  • What it means for you: If you live in China or care about global nutrition, this shows that nutrition programs are working. However, vitamin A deficiency remains a concern for children and women, so continued efforts to improve diets with vitamin A-rich foods (like carrots, sweet potatoes, and leafy greens) are still important

The Research Details

This research analyzed existing health information from a large global database called the Global Burden of Disease (GBD), which tracks health problems across countries. The researchers looked at three main measures: how many new cases of vitamin A deficiency appeared each year (incidence), how many people had it at any given time (prevalence), and how much it affected people’s quality of life and lifespan (disability-adjusted life years, or DALYs). They used a statistical method called Joinpoint regression to find patterns in the data from 1990 to 2021, calculating how much the rates changed each year. Then they used a more advanced method called Bayesian Age-Period-Cohort modeling to make predictions about what would happen from 2022 to 2050, taking into account how age, time period, and birth year all affect vitamin A deficiency rates.

This approach is important because it lets researchers understand long-term trends without needing to follow individual people for decades. By analyzing national health data, they can see the big picture of whether public health efforts are working and predict future needs. This helps governments and health organizations plan where to focus their nutrition programs.

This study used data from a well-established, peer-reviewed global health database, which is a strength. However, the quality depends on how accurately each country reported its health information. The study looked at trends over 31 years, which gives confidence in the patterns found. The researchers used standard statistical methods that are widely accepted in health research. One limitation is that this analysis can show trends but cannot explain exactly why vitamin A deficiency is decreasing—it could be better diets, supplements, food fortification, or a combination of factors.

What the Results Show

From 1990 to 2021, vitamin A deficiency in China showed a strong downward trend across all measures. The age-standardized incidence rate (new cases per 100,000 people) dropped by about 5.3% each year, the prevalence rate (total cases per 100,000 people) also dropped by about 5.3% each year, and the disability-adjusted life year rate (measuring impact on health and life expectancy) dropped by about 3.9% each year. These decreases were consistent and statistically significant, meaning they weren’t due to chance. Looking forward, the models predict that from 2022 to 2050, the disease burden will continue to improve but at a slower rate. The disability-adjusted life year rate is expected to drop from 3.17 per 100,000 people in 2022 to 2.70 per 100,000 in 2050. Even more dramatically, new cases are predicted to fall from 1,838 per 100,000 in 2022 to 270 per 100,000 in 2050, and total cases are expected to drop from 1,835 per 100,000 to 268 per 100,000.

The research found important differences between groups. Females had higher rates of vitamin A deficiency than males throughout the entire time period. Children had much higher rates than adults, which makes sense because growing bodies need more vitamins. These patterns suggest that nutrition programs should pay special attention to girls and young children, who appear to be at higher risk.

This is one of the first detailed studies specifically looking at vitamin A deficiency trends in China. It confirms what global health experts have observed: that vitamin A deficiency is decreasing in many countries as nutrition improves and food fortification programs expand. However, China’s improvement rate is particularly strong, suggesting that public health efforts there have been effective.

This study analyzed existing data rather than conducting new research, so it can show trends but not explain the exact causes of improvement. The predictions for 2022-2050 assume that current trends will continue, but unexpected changes in diet, economy, or public health policy could alter these projections. The study also depends on the accuracy of health data reported by different regions in China, which may vary. Additionally, the study doesn’t distinguish between different types of vitamin A deficiency or different causes, so it provides a general picture rather than detailed information about specific populations or regions.

The Bottom Line

Based on this research, public health efforts to prevent vitamin A deficiency in China should continue and possibly expand, with special focus on children and women. Recommendations include: (1) Continue food fortification programs that add vitamin A to staple foods like rice and flour (high confidence); (2) Promote consumption of vitamin A-rich foods including orange vegetables, dark leafy greens, and animal products (high confidence); (3) Consider targeted supplementation programs for high-risk groups like young children and pregnant women (moderate confidence); (4) Maintain nutrition education programs to help families understand the importance of vitamin A (moderate confidence).

This research is most relevant to public health officials, nutritionists, and policymakers in China who are planning nutrition programs. It’s also important for parents and caregivers of young children, especially girls, who should ensure adequate vitamin A intake. Healthcare providers should be aware of these trends when counseling patients. People in other countries with similar development levels may also find this information relevant. However, this research is less directly applicable to people in countries with very different food systems or vitamin A deficiency rates.

The improvements shown in this research happened gradually over 31 years (1990-2021), so vitamin A deficiency is not something that improves overnight. If individuals or families increase their vitamin A intake through diet or supplements, they may notice improved vision, skin health, and immune function within weeks to months. However, population-level changes in deficiency rates take years or decades to become apparent. The projections suggest continued gradual improvement through 2050.

Want to Apply This Research?

  • Track weekly servings of vitamin A-rich foods (orange vegetables like carrots and sweet potatoes, dark leafy greens like spinach, and animal products like eggs and liver). Goal: 3-4 servings per week minimum.
  • Users can set a daily reminder to include one vitamin A-rich food in their meals. The app could suggest specific recipes featuring carrots, sweet potatoes, spinach, kale, or other accessible sources. For parents, track children’s vitamin A intake separately to ensure adequate nutrition for growing bodies.
  • Monthly review of vitamin A food intake patterns. Users can photograph meals containing vitamin A sources to build awareness. For families with young children or pregnant/nursing women, track supplementation if recommended by healthcare providers. Set seasonal goals, as some vitamin A sources (like fresh greens) may be more available at certain times of year.

This research analyzes population-level health trends in China and should not be used for individual medical diagnosis or treatment. If you or a family member suspects vitamin A deficiency (symptoms may include night blindness, dry eyes, or frequent infections), consult a healthcare provider for proper testing and personalized recommendations. This article is for informational purposes only and does not replace professional medical advice. Vitamin A supplementation should only be undertaken under medical supervision, as excessive vitamin A can be harmful. Pregnant women should be especially cautious about vitamin A intake and should consult their healthcare provider before taking supplements.