Researchers studied vitamin A deficiency in China from 1990 to 2021 and predicted what would happen by 2035. They found great news: vitamin A deficiency has dropped dramatically, especially in young children. However, there’s a concerning trend emerging in older adults aged 50-74, where the problem is getting worse. The study shows that while prevention efforts have worked well for kids, aging populations are creating new challenges. Understanding these patterns helps doctors and public health officials plan better strategies to protect vulnerable groups like children, pregnant women, and elderly people.

The Quick Take

  • What they studied: How vitamin A deficiency has changed in China over 30 years and what experts predict will happen in the next 10 years
  • Who participated: This wasn’t a traditional study with volunteers. Instead, researchers analyzed health data from millions of Chinese people collected by the Global Burden of Disease Database, looking at information from 1990 through 2021
  • Key finding: Vitamin A deficiency dropped significantly in children under 5 (declining about 6% each year), but surprisingly started increasing in people aged 50-74 in recent years. By 2035, the overall trend should continue improving, but more slowly in older adults
  • What it means for you: If you’re a parent in China, the good news is your child’s risk of vitamin A deficiency is much lower than it was 30 years ago. If you’re over 50, you should pay more attention to getting enough vitamin A through diet or supplements. The findings suggest public health programs need to shift focus from just protecting children to also protecting aging populations

The Research Details

Researchers didn’t conduct experiments with people. Instead, they used a clever statistical approach called the Bayesian age-period-cohort model to analyze existing health data from the Global Burden of Disease Database. This database collects health information from countries worldwide, including China. They looked at three main measurements: 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 disability and death it caused (measured as DALYs—disability-adjusted life years). They used a tool called Joinpoint regression to identify when trends changed direction and how fast they were changing. Then they used their statistical model to make predictions about what would happen by 2035.

This approach is powerful because it lets researchers spot patterns across millions of people without needing to recruit volunteers or do expensive experiments. By breaking down the data by age and sex, they could see which groups were improving and which were struggling. The predictions for 2035 help governments plan public health programs before problems get worse. Understanding whether changes are due to better prevention, population aging, or other factors helps officials target solutions more effectively.

This study used established, peer-reviewed data from the Global Burden of Disease Database, which is widely respected in public health research. The statistical methods (Joinpoint regression and Bayesian modeling) are standard tools used by health researchers worldwide. However, the study relies on the accuracy of the underlying data collected by different countries, which can vary in quality. The predictions for 2035 assume current trends continue, which may not happen if new prevention programs are introduced or if people’s diets change significantly.

What the Results Show

From 1990 to 2021, vitamin A deficiency in China improved dramatically overall. Children under 5 saw the biggest improvement, with cases dropping about 6% every year—that’s remarkable progress over three decades. Young people and adolescents also saw significant improvements in how much the disease affected their health and quality of life. The main reason for this success was better prevention and nutrition programs, not just population changes. Women had higher rates of vitamin A deficiency than men throughout the study period, but men experienced more severe health consequences when they did have the deficiency. Interestingly, while the overall trend was positive, something unexpected happened: people aged 50-74 started experiencing more vitamin A deficiency in recent years, reversing decades of progress in that age group.

The research revealed important differences between age groups and sexes. Children under 5 carried the heaviest burden of vitamin A deficiency throughout the entire study period, making them the priority for prevention efforts. Women consistently had higher rates of the condition, possibly because of pregnancy and breastfeeding demands, but their health outcomes were generally better than men’s. The study found that population aging—meaning China has more older people now—is actually creating more cases of vitamin A deficiency, even if the percentage of people affected is staying the same. This is a critical insight: success in preventing childhood deficiency doesn’t automatically solve the problem for aging populations.

This study confirms what other research has shown: childhood vitamin A deficiency prevention programs work. China’s improvements in young children match what other developing countries have achieved through similar programs. However, the finding about increasing deficiency in older adults aged 50-74 is concerning and suggests that previous public health strategies may have overlooked this growing population. The study also aligns with global research showing that women tend to have higher rates of vitamin A deficiency, likely due to biological and nutritional demands during reproductive years.

The study relies on data quality from different sources, which may not be equally accurate across all regions of China or all time periods. The predictions for 2035 assume that current trends will continue, but new prevention programs, dietary changes, or economic shifts could alter the actual outcomes. The study doesn’t explain why older adults are experiencing increased vitamin A deficiency—it only identifies that it’s happening. Additionally, the data may not capture all cases of vitamin A deficiency, especially in rural or underserved areas where people might not seek medical care.

The Bottom Line

People in China, especially those over 50, should ensure adequate vitamin A intake through diet (foods like carrots, sweet potatoes, spinach, and liver) or supplements if recommended by a doctor. Parents should continue supporting childhood nutrition programs that have proven so successful. Public health officials should develop new strategies specifically targeting older adults and pregnant women. Healthcare providers should screen older patients for vitamin A deficiency, particularly those with poor nutrition or digestive problems. These recommendations have moderate to strong evidence based on the study’s findings.

Everyone in China should care about these findings, but especially: parents of young children (to maintain the progress made), women of childbearing age and pregnant women (who have higher needs), people over 50 (who face increasing risk), and public health officials (who need to plan programs). People outside China can learn from China’s success in preventing childhood deficiency and from the emerging challenge of protecting aging populations. Healthcare providers should use this information to better screen and counsel patients about vitamin A needs.

If you improve your vitamin A intake today, you may notice better vision and immune function within weeks to months. However, preventing serious vitamin A deficiency is a long-term commitment. The study’s predictions suggest that without intervention, the problem in older adults will continue growing through 2035. Public health improvements typically take years to show measurable results in populations.

Want to Apply This Research?

  • Users should track daily vitamin A intake in micrograms (RAE—retinol activity equivalents). Adults need 700-900 mcg daily. Users can log foods like carrots, sweet potatoes, spinach, kale, liver, and fortified milk to monitor whether they’re meeting daily targets
  • Set a daily reminder to include one vitamin A-rich food at lunch or dinner. For example: add spinach to pasta, eat a sweet potato as a side dish, or include carrots in a salad. Users can photograph their meals to build awareness of their vitamin A intake patterns
  • Track weekly vitamin A intake averages rather than daily totals, since vitamin A is fat-soluble and the body stores it. Users aged 50+ should set monthly check-ins to review their intake and adjust if falling short. Those with digestive issues or taking certain medications should note any changes in vision or health and discuss with their doctor

This research summary is for educational purposes only and should not replace professional medical advice. If you suspect you have vitamin A deficiency or have concerns about your vitamin A intake, consult with a healthcare provider or registered dietitian. This is especially important for pregnant women, people with digestive disorders, or those taking medications that affect nutrient absorption. The study’s predictions for 2035 are based on current trends and may not account for future changes in public health policy or individual circumstances. Always seek personalized medical advice from qualified healthcare professionals.