On this page
- How can a country on the equator be short of vitamin D?
- How much sunlight are Malaysians actually getting?
- How common is vitamin D deficiency in Malaysia, and who is most affected?
- Does low vitamin D actually explain feeling tired?
- Does vitamin D help with healthy ageing, fractures and falls?
- How much vitamin D do Malaysians need, and how would you know your level?
- What actually helps your vitamin D level, and where is the safe ceiling?
- When is your tiredness not about vitamin D?
Malaysia sits three degrees from the equator, yet vitamin D deficiency is common here because little sun reaches skin. Asian adults in Kuala Lumpur received less ultraviolet than Asian adults in an Aberdeen summer, and their yearly totals from sunlight plus diet came out level. Indoor days, covering clothing, shade and darker skin cut synthesis; food carries little.
This page sits under our cluster on foundational nutrients and under the pillar guide why am I always tired?, alongside iron, B12 or vitamin D. The question here is narrower: why a country on the equator ends up short of the one nutrient sunlight makes — and whether that is what is making you tired.
- Measured sun exposure in Kuala Lumpur sat below an Aberdeen summer. Ultraviolet-recording badges put Asian adults in Kuala Lumpur (3°N) at 0.14 to 0.20 standard erythemal doses a day, against 0.25 for Asian adults in Aberdeen (57°N) in summer (Jamil et al., Public Health Nutrition, 2018).
- Across a full year the two cities came out level. Estimated total vitamin D from sunlight plus diet came out at 5.75 µg/day in Aberdeen against 6.15 in Kuala Lumpur (p = 0.78) — Malaysians get their sun spread thin, not concentrated (Jamil et al., 2018).
- Low vitamin D turned up in both Malaysian samples cited here — 858 Kuala Lumpur teachers and 1,016 fifteen-year-olds — but the spread between ethnic groups is very wide. Among the teachers, 67.4 percent were below 20 ng/ml (50 nmol/l): 80.9 percent of Indian against 25.1 percent of Chinese participants (Shafinaz & Moy, BMC Public Health, 2016; Quah et al., PLOS One, 2018).
- Within Malaysia, who you are and how you dress out-predicted where you live. Among those 1,016 Malaysian 15-year-olds the factors surviving adjustment were sex (5.5x), Indian and Malay ethnicity (4.3x and 3.2x) and always wearing long sleeves (2.4x); skin pigmentation alone and urban-versus-rural school location were not (Quah et al., PLOS One, 2018).
- The fatigue evidence is split, and the split is the whole point. A placebo-controlled trial in 120 deficient adults found a single large dose improved fatigue scores; a genetic analysis of 327,478 people found no evidence that vitamin D status causes tiredness across a general population (Nowak et al., Medicine, 2016; Havdahl et al., Scientific Reports, 2019).
How can a country on the equator be short of vitamin D?
Because the vitamin is made in skin, not in sky. Ultraviolet B has to land on bare skin in sufficient dose to convert a cholesterol precursor into cholecalciferol, and most of a modern Malaysian day interrupts that step: air-conditioned hours, deliberate shade, covering clothing, sunscreen, and darker skin, whose melanin absorbs ultraviolet B first.
A 2022 review of Malaysian vitamin D status in Nutrients puts the skin part plainly: dark skin is known to have a low capacity to produce vitamin D
, because melanin absorbs ultraviolet B and shields the skin underneath. Melanin is a filter, not a defect — but a filter that works well in equatorial sun also means the same ten minutes outdoors yields less vitamin D for a darker-skinned person.
The sky above that filter is less generous than the map suggests. In the Kuala Lumpur arm of the 2018 ultraviolet-badge study, mean cloud cover ran at 7.0 oktas a day — roughly seven-eighths of the sky covered. The same authors record that ultraviolet B intensity can be reduced by up to 50% in some shady environments
(Jamil et al., Public Health Nutrition, 2018).
Malaysian clinicians write about it directly. In The Star in May 2025, consultant paediatrician and paediatric endocrinologist Dr Jeanne Wong Sze Lyn put the objection most Malaysians raise first, and answered it.
We live in a sunny country, surely we cannot be low in vitamin D? Vitamin D deficiency is surprisingly common in Malaysia.Dr Jeanne Wong Sze Lyn, consultant paediatrician and paediatric endocrinologist, The Star, May 2025
She attributes that deficiency to indoor lifestyles in offices, classrooms, malls and cars, to sun-avoidant behaviour including covering up and sunscreen use, to air pollution blocking ultraviolet B, and to higher body fat percentages, which the article links to lower circulating vitamin D. Availability of sunlight and exposure to sunlight are two different measurements, and only the second makes vitamin D.
How much sunlight are Malaysians actually getting?
Less than most people assume. Ultraviolet-recording badges put Asian adults in Kuala Lumpur at 0.14 to 0.20 standard erythemal doses a day, against 0.25 in an Aberdeen summer. Their estimated yearly total vitamin D from sunlight plus diet was comparable — 5.75 µg/day in Aberdeen against 6.15 in Kuala Lumpur (p = 0.78). Equatorial sun buys parity, not surplus.
How was Malaysians' sun exposure actually measured?
The study, published in Public Health Nutrition in 2018, recruited 115 Asian adults in Kuala Lumpur at 3°N and 85 in Aberdeen at 57°N, aged 20 to 50. It did not ask people how much sun they got: polysulfone film badges were worn on outdoor clothing for seven consecutive days per season and read spectrophotometrically at 330 nm, turning absorbance into the dose actually received. One SED is the standard unit for a skin-reddening dose of ultraviolet.
The seasonal shape is the part usually missed. Aberdeen's advantage is a summer spike and nothing else: 0.25 SED/day in summer and 0.22 in spring, but 0.04 in autumn and 0.02 in winter, while Kuala Lumpur never left its 0.14 to 0.20 band. With diet added, Aberdeen reached 8.45 µg a day in summer against 6.03 µg in the Kuala Lumpur southwest monsoon and 5.35 µg in the northeast monsoon. The equator bought only parity, because so little of the ultraviolet on offer reached skin.
The authors explain the gap without any appeal to willpower: outdoor time in Kuala Lumpur was spent in shade, because of the heat and a cultural preference for fair skin, and cloud, haze and tall buildings did the rest. Diet ran the same way — 1.83 to 2.05 µg a day against Aberdeen's 3.50 µg.
Does Malaysian food supply enough vitamin D?
Malaysian law directs only two foods to be fortified with vitamin D — cereal-based foods for infants and young children, and table margarine — so for most adults here food is a minor contributor and sunlight is the major one being missed (Md Isa et al., Nutrients, 2022).
| Food | Vitamin D it carries | Status in Malaysia |
|---|---|---|
| Table margarine | 250 to 350 IU (about 6.3 to 8.8 µg) per 100 g | Mandatory under the Food Regulations 1985 |
| Cereal-based foods for infants and young children | 1 to 3 µg per 100 kcal | Mandatory — the only other food directed to be fortified, and not an adult food |
| Fortified milk | about 1.3 µg per 100 g | Voluntary |
| Fortified yoghurt | about 1.2 µg per 100 g | Voluntary |
| Fatty fish (salmon, mackerel, herring, tuna, sardines), cod liver oil, egg yolk and mushrooms | Named as the natural food sources of vitamin D; the review reports no Malaysian per-serving figure for them | Not covered by any vitamin D fortification requirement |
The same review is blunt that vegetables, meat, and poultry are poor sources of vitamin D
— and on many plates here those three are most of the meal, which is our reading, not the review's. The fortified items are thinner than they look: at about 1.3 µg per 100 g, fortified milk alone would take well over a litre a day to reach the 15 µg RNI — which is arithmetic, not a serving suggestion. Fatty fish, cod liver oil, egg yolk and mushrooms are the natural sources the Malaysian review names, and none is a daily staple for most people here.
How common is vitamin D deficiency in Malaysia, and who is most affected?
Low vitamin D turned up in both Malaysian samples cited here — 858 Kuala Lumpur teachers and 1,016 fifteen-year-olds. Among the teachers, 67.4 percent were below 50 nmol/l, and the ethnic spread is very wide: 80.9 percent of Indian against 25.1 percent of Chinese participants. Among the adolescents, 33 percent were at or below the same threshold.
The adult picture comes from a 2016 cross-sectional study in BMC Public Health covering 858 permanent teachers in Kuala Lumpur government secondary schools, counting serum 25(OH)D below 20 ng/ml (50 nmol/l) as deficient. Prevalence was 67.4 percent, and the weighted mean — the sample average after adjusting for how participants were sampled — was 17.97 ng/ml, give or take 7.32. By ethnicity: Indian 80.9 percent, Malay 75.6 percent, others 44.9 percent, Chinese 25.1 percent. The authors concluded that skin pigmentation and gender based behaviours were more dominant in contributing to serum 25(OH)D level
. Two caveats keep this honest: the sample was 90.9 percent female and the response rate 41 percent, so 67.4 percent describes teachers who chose to take part, not Malaysian adults as a population.
That study was built around body fat, and its answer is more careful than the popular version. Serum 25(OH)D was negatively associated with BMI and with body fat percentage — as one went up, the other tended to go down. In the multivariate model, the analysis that weighs every factor at once, higher BMI and larger waist circumference stayed significant while body fat percentage did not. Shafinaz and Moy nonetheless concluded adiposity was not the main risk factor: BMI and waist circumference added roughly 1 percent of the explained variation — how much of the difference between people the model accounts for — against 16.9 percent for ethnicity and 7.1 percent for gender.
Who is most at risk in the Malaysian data?
The adolescent study is the one that ranks the risk factors. A 2018 analysis in PLOS One covered 1,016 fifteen-year-olds from the Malaysian Health and Adolescents Longitudinal Research Team cohort, using 50 nmol/l or below as deficient. Prevalence was 33 percent overall but split sharply: 47 percent of girls against 11 percent of boys, and 36 percent of Malay, 32 percent of Indian and 8 percent of Chinese participants. Adjusted, the odds of deficiency were 5.5 times higher for girls (95% CI 3.4 to 7.5 — the range the true figure most plausibly sits in), 4.3 for Indian participants (1.6 to 12.0), 3.2 for Malay participants (1.3 to 8.0) and 2.4 for those who always wore long sleeves (1.1 to 5.4).
What did not reach significance is as instructive as what did: skin pigmentation on its own, cloud cover, urban-versus-rural school location and reported use of sunscreen, hats, veils or umbrellas all fell away once other factors were accounted for, and duration of outdoor activity survived only unadjusted. What survived adjustment in this Malaysian sample was who a person is and how much skin stays covered, not where the school sat or how cloudy the sky was. That is not a reversal of the melanin mechanism above: in this cohort ethnicity carried pigmentation, dress and daily routine together, so measured pigmentation on its own had little left to explain once ethnicity was already in the model. It describes a cohort, not anyone's wardrobe.
Sunlight and skin do not exhaust the risk list. The 2022 Nutrients review names breastfed infants among the vulnerable groups at risk of low vitamin D status, along with the elderly, the obese, those on medications, and those characterized by fat malabsorption and geophysical factors
. Those risks have nothing to do with how much sun a country gets.
Does low vitamin D actually explain feeling tired?
Sometimes, and mainly in people who were genuinely deficient to begin with. A placebo-controlled trial in 120 deficient adults reporting fatigue found that a single large dose improved fatigue scores. A genetic analysis in 327,478 people found no evidence that vitamin D status causes tiredness across a general population. Those two results describe different people, not a contradiction.
The trial, published in Medicine in 2016, enrolled 120 otherwise healthy adults who presented with fatigue and had serum 25(OH)D below 20 µg/l — the same number as the 20 ng/ml cut-off the Malaysian studies use. They received a single oral dose of 100,000 units of vitamin D3 or placebo and were reassessed after four weeks. Fatigue Assessment Scale scores fell 3.3 ± 5.3 points on vitamin D against 0.8 ± 5.3 on placebo (p = 0.01), and 72 percent reported improvement against 50 percent on placebo, an odds ratio of 2.63 (95% CI 1.23 to 5.62). The authors concluded that vitamin D treatment significantly improved fatigue in otherwise healthy people with vitamin D deficiency.
The counterweight is larger. A 2019 study in Scientific Reports used two-sample Mendelian randomisation, which infers causation from genetic variants people are born with, not lifestyles they adopt. Among 327,478 UK Biobank participants of European descent, 19,526 (5.96 percent) reported tiredness or low energy nearly every day over the past fortnight. Using seven genetic variants that lower 25(OH)D, the odds ratio for fatigue was 1.05 (95% CI 0.87 to 1.27) per standard deviation decrease; two alternative methods gave 1.06 (0.86 to 1.32) and 1.16 (0.85 to 1.59). Every interval crosses one, so every one of those results is compatible with no effect at all.
Our results suggest that a clinically relevant protective effect of 25OHD-levels on fatigue is unlikely. Therefore, vitamin D supplementation of the general population to raise 25OHD-levels is not likely to be useful in preventing fatigue.Havdahl, Mitchell, Paternoster & Davey Smith, Scientific Reports, 2019
The honest synthesis is that correcting a measured deficiency helped deficient people over four weeks, while nudging vitamin D upwards across a population that was mostly not deficient did not appear to move fatigue at all.
| What you often hear | What the research actually shows |
|---|---|
| Vitamin D gives you energy | Vitamin D is not a fuel. In a general population, genetic analysis in 327,478 people found no evidence that lower 25(OH)D causes fatigue, OR 1.05 (0.87 to 1.27) (Havdahl et al., 2019) |
| Darker skin just needs a bit longer in the sun | Melanin absorbs ultraviolet B, so the same minutes outdoors yield less vitamin D (Md Isa et al., 2022) — but among 1,016 Malaysian 15-year-olds, measured skin pigmentation on its own did not survive adjustment, while Indian and Malay ethnicity did, at 4.3x and 3.2x (Quah et al., 2018) |
| If you feel tired, top up and see | The trial that showed a fatigue benefit selected people already below 20 µg/l; benefit in people who are not deficient has not been shown (Nowak et al., 2016) |
| More vitamin D means more benefit | In 688 adults aged 70 and over, doses of 1,000 IU a day and above did not prevent falls, and higher doses carried safety signals (Appel et al., 2021) |
Does vitamin D help with healthy ageing, fractures and falls?
The large trials urge modesty. Among 25,871 midlife and older adults not selected for deficiency, 2,000 IU a day over a median 5.3 years did not lower fracture risk. Among 688 adults aged 70 and over at raised fall risk, 1,000 IU a day or more did not prevent falls, and the higher doses carried safety signals, not extra benefit.
The fracture result comes from VITAL, in the New England Journal of Medicine in 2022, which randomised 25,871 midlife and older adults to 2,000 IU of vitamin D3 daily or placebo for a median 5.3 years and recorded 1,991 fractures in 1,551 people. The hazard ratio for total fractures — the fracture rate on vitamin D divided by the rate on placebo, where 1.00 means no difference — was 0.98 (95% CI 0.89 to 1.08, p = 0.70): essentially the same fracture rate in both groups. Supplementation, the authors stated, did not result in a significantly lower risk of fractures than placebo among generally healthy midlife and older adults who were not selected for vitamin D deficiency, low bone mass, or osteoporosis
.
The falls result comes from STURDY, in Annals of Internal Medicine in 2021, which compared 1,000, 2,000 and 4,000 IU a day against a 200 IU control in 688 adults aged 70 and over with elevated fall risk, over two years. The 1,000 IU group did not differ from control (hazard ratio 0.94, 95% CI 0.76 to 1.15, p = 0.54); among those on 1,000 IU or more the hazard ratio was 1.87 (1.03 to 3.41) for a serious fall and 2.48 (1.13 to 5.46) for a fall with hospitalisation. Supplementation at 1,000 IU a day or higher did not prevent falls.
Both trials tested extra vitamin D in adults not selected for deficiency, and in both the extra did not deliver. Neither shows a genuine shortfall is harmless — but at the top of the dose range the risk column stopped being empty.
How much vitamin D do Malaysians need, and how would you know your level?
Malaysia's RNI 2017 sets 15 micrograms (600 IU) a day for adults aged 19 to 65 and 20 micrograms (800 IU) above 65, on the explicit assumption of minimal sunlight exposure. Status itself is judged from a blood test measuring 25-hydroxyvitamin D, not from symptoms.
The recommended nutrient intake figures come from the National Coordinating Committee on Food and Nutrition and are reproduced in the 2022 Nutrients review, which sets them out with the assumptions of minimal sunlight exposure
. That assumption describes a great many office-based Malaysians.
Reading a result is less tidy than it looks, because the cut-off moves the headline. Malaysian studies have used below 30 nmol/l for deficiency with 30 to 50 nmol/l as insufficiency, a single below-50 nmol/l cut-off, and below 37.5 nmol/l. So two honest studies of the same population can report very different prevalence figures without either being wrong.
What test tells you your vitamin D level?
The Malaysian Vitamin D Special Interest Group, writing in Osteoporosis International in 2023, recommends serum or plasma 25-hydroxyvitamin D — 25(OH)D — as the biomarker of vitamin D status: that is the measurement to raise with a qualified healthcare professional, not intake and not symptoms. The same group recommends Malaysia adopt the US Endocrine Society definitions of deficiency and insufficiency, that assessment be targeted at identified high-risk groups rather than offered to everyone, and that Malaysian laboratories participate widely in the Vitamin D Standardization Program (Lee et al., Osteoporosis International, 2023).
The standardisation point matters: calling for widespread laboratory participation in a standardisation programme implies participation is not yet widespread, so two 25(OH)D results from two Malaysian laboratories cannot be assumed directly comparable. The same paper recommends a comprehensive nationwide vitamin D status study — and a recommendation to build one implies there is not one yet.
What actually helps your vitamin D level, and where is the safe ceiling?
Short, regular daylight on bare skin, realistic expectations of food, and supplementation reserved for a measured need or a clear risk profile. There is a ceiling: the European Food Safety Authority sets the tolerable upper intake level for adults at 100 micrograms (4,000 IU) a day, and the trial evidence gives no reason to push towards it.
- Take a little sun on purpose. Writing in The Star, Dr Jeanne Wong Sze Lyn suggests 10 to 20 minutes of direct sun two to three times a week, best between late morning and early afternoon. Malaysia's 2023 position paper only proposes a national alliance to progress safe-sun-exposure initiatives, so treat any single figure as a starting point, not settled national guidance.
- Remember that shade is not sun. Ultraviolet B intensity can be reduced by up to 50 percent in some shady environments (Jamil et al., Public Health Nutrition, 2018), so an hour outdoors under cover is not the same exposure as ten minutes in the open.
- Do not expect the plate to carry it. Adults measured in Kuala Lumpur averaged 1.83 to 2.05 µg a day from food, against an RNI of 15 µg (Jamil et al., Public Health Nutrition, 2018). The table above is the whole legal picture: two foods directed to be fortified, one of them an infant food, everything else voluntary (Md Isa et al., Nutrients, 2022).
- If you sit in one of the higher-risk groups listed above, ask about a test rather than guessing. A blood test answers what a symptom list cannot.
- More is not better. In the STURDY trial the higher doses did worse than the lower one. The European Food Safety Authority's tolerable upper intake level for adults is 100 µg (4,000 IU) a day, derived from a lowest-observed-adverse-effect level of 250 µg a day with an uncertainty factor of 2.5, using persistent hypercalciuria as the critical endpoint (EFSA NDA Panel, EFSA Journal, 2023).
- None of this is an argument for burning. Sun protection advice from a qualified healthcare professional outranks a general wellness page, and nothing here suggests trading skin health for a blood number.
When is your tiredness not about vitamin D?
Frequently. Vitamin D is one nutrient among several, and nutrient status is one of five drivers of everyday tiredness we cover. If tiredness persists after a level has been corrected, or arrives alongside symptoms that have nothing to do with nutrition, that is a question for a qualified healthcare professional rather than a bigger supplement.
In a genetic analysis of 327,478 UK Biobank participants, nearly 6 percent reported tiredness or low energy nearly every day, and the study found no evidence vitamin D status caused it (Havdahl et al., Scientific Reports, 2019).
If you arrived from the symptom side of the question, our sibling page sets out what low vitamin D actually feels like and how that overlaps with low iron and low B12. The nearest neighbours are worth ruling out on their own evidence: low ferritin without anaemia, zinc deficiency, and the honest case for and against a general multivitamin. The climate is a real contributor here, covered in heat, humidity and tiredness, and the age-related side in why do I feel more tired as I get older. Vitamin D is a plausible contributor to everyday tiredness in Malaysia for people who are genuinely deficient, and it is not the explanation for tiredness in general. The pillar guide on why am I always tired sets out the full picture.
Frequently asked questions
Why is vitamin D deficiency common in Malaysia when it is sunny all year?
Because sunlight has to reach bare skin. Asian adults in Kuala Lumpur received 0.14 to 0.20 standard erythemal doses a day against 0.25 for Asian adults in an Aberdeen summer, and across a full year the two cities' estimated total vitamin D from sunlight plus diet was merely comparable. The authors blamed shade, a preference for fair skin, heat, 7.0 oktas of cloud, haze and tall buildings. Covering clothing and darker skin reduce synthesis further.
How common is vitamin D deficiency among Malaysians?
Low vitamin D turned up in both Malaysian samples cited here, and the ethnic spread is very wide. Among 858 Kuala Lumpur teachers, 90.9 percent of them women, 67.4 percent were below 50 nmol/l — 80.9 percent of Indian against 25.1 percent of Chinese participants. Among 1,016 fifteen-year-olds, 33 percent were at or below that same threshold, split 47 percent of girls against 11 percent of boys, and 8 percent of Chinese participants.
Does taking vitamin D fix tiredness?
It depends who is taking it. In 120 otherwise healthy adults reporting fatigue with serum 25(OH)D below 20 µg/l — the same number as the 20 ng/ml cut-off the Malaysian studies use — a single 100,000-unit dose improved Fatigue Assessment Scale scores against placebo over four weeks (p = 0.01). In 327,478 UK Biobank participants, a genetic analysis found no evidence that lower vitamin D causes fatigue, odds ratio 1.05 (95% CI 0.87 to 1.27).
How much sun exposure do I actually need in Malaysia?
In The Star, May 2025, consultant paediatric endocrinologist Dr Jeanne Wong Sze Lyn suggests 10 to 20 minutes of direct sun two to three times a week, best between late morning and early afternoon. Because melanin reduces how efficiently skin makes vitamin D, requirements vary with skin tone — and Malaysia's vitamin D specialists have only proposed a national alliance on safe sun exposure, so treat this as a starting point, not settled national guidance.
Should I get my vitamin D level tested?
That is a question for a qualified healthcare professional. What the Malaysian evidence shows is that risk is not evenly spread: women, people who are always covered, people whose days are entirely indoors, older adults, breastfed infants and people with obesity or fat malabsorption recur in the literature. The 2023 Malaysian position paper recommends serum or plasma 25-hydroxyvitamin D as the biomarker, and targeted assessment of identified high-risk groups rather than testing everyone.
References
- Estimated vitamin D synthesis and dietary vitamin D intake among Asians in two distinct geographical locations (Kuala Lumpur, 3°N v. Aberdeen, 57°N) and climates (Jamil, Yew, Hafizah, Gray, Poh & Macdonald, Public Health Nutrition, 2018;21(17):3118-3124) — supports the 115 and 85 participants, the polysulfone badge method read at 330 nm, the 0.14 to 0.20 versus 0.25 SED/day figures, the 1.83 to 2.05 versus 3.50 µg/day dietary intakes, the 5.35 to 8.45 µg/day totals, the 50 percent shade reduction, the 7.0 oktas cloud cover and the tall-buildings explanation, plus the Aberdeen seasonal ultraviolet figures (spring 0.22, summer 0.25, autumn 0.04 and winter 0.02 SED/day) and the comparable full-year totals of 5.75 µg/day in Aberdeen against 6.15 µg/day in Kuala Lumpur (p = 0.78).
- Vitamin D level and its association with adiposity among multi-ethnic adults in Kuala Lumpur, Malaysia: a cross sectional study (Shafinaz & Moy, BMC Public Health, 2016;16:232) — supports the 858 teachers, the 41 percent response rate, the 90.9 percent female sample, the below-20 ng/ml (50 nmol/l) cut-off, the 67.4 percent overall prevalence, the 80.9 / 75.6 / 44.9 / 25.1 percent ethnic breakdown, the 17.97 ± 7.32 ng/ml weighted mean and the quoted conclusion, plus the negative associations of serum 25(OH)D with BMI (β = −0.23) and body fat percentage (β = −0.14), the 25.66 ± 5.06 kg/m² mean BMI and 28.1 ± 8.0 percent mean body fat, the multivariate significance of BMI and waist circumference, and the conclusion that adiposity was not the main risk factor.
- Risk factors of vitamin D deficiency among 15-year-old adolescents participating in the Malaysian Health and Adolescents Longitudinal Research Team Study (MyHeARTs) (Quah et al., PLOS One, 2018;13(7):e0200736) — supports the 1,016 participants, the 50 nmol/l cut-off, the 33 percent overall and 47 versus 11 percent sex split, the 36 / 32 / 8 percent ethnic split, and the adjusted odds ratios of 5.5 (female), 4.3 (Indian), 3.2 (Malay) and 2.4 (always wearing long sleeves), plus the factors that were not significant.
- An Update on Vitamin D Deficiency Status in Malaysia (Md Isa, Mohd Nordin, Mahmud & Hashim, Nutrients, 2022;14(3):567) — supports the Malaysian RNI 2017 values of 15 µg (600 IU) for ages 19-65 and 20 µg (800 IU) above 65 with the minimal-sunlight assumption, the skin-synthesis and melanin quotations, the varying deficiency cut-offs used across Malaysian studies, the Food Regulations 1985 detail that margarine and processed cereal-based foods for infants and young children are the only foods directed to be fortified with vitamin D under law, the voluntary milk (1.3 µg/100 g) and yoghurt (1.2 µg/100 g) figures, the named natural food sources and the judgement that vegetables, meat and poultry are poor sources, and the list of vulnerable groups including breastfed infants, the elderly, the obese, those on medications and those with fat malabsorption.
- Effect of vitamin D3 on self-perceived fatigue: a double-blind randomized placebo-controlled trial (Nowak et al., Medicine (Baltimore), 2016;95(52):e5353) — supports the 120 participants, the mean age 29 ± 6 and 53 percent women, the below-20 µg/l inclusion threshold, the single 100,000-unit dose, the four-week follow-up, the -3.3 ± 5.3 versus -0.8 ± 5.3 Fatigue Assessment Scale change at p = 0.01, the 72 versus 50 percent improvement rates and the odds ratio of 2.63 (1.23 to 5.62).
- Investigating causality in the association between vitamin D status and self-reported tiredness (Havdahl, Mitchell, Paternoster & Davey Smith, Scientific Reports, 2019;9:2880) — supports the 327,478 UK Biobank participants, the 19,526 (5.96 percent) reporting tiredness, the seven genetic instruments, the odds ratios of 1.05 (0.87 to 1.27), 1.06 (0.86 to 1.32) and 1.16 (0.85 to 1.59), and the quoted conclusion.
- Supplemental vitamin D and incident fractures in midlife and older adults (LeBoff et al., New England Journal of Medicine, 2022;387(4):299-309) — supports the 25,871 participants, the 50.6 percent women and 20.2 percent Black composition, the 2,000 IU daily dose, the median 5.3-year follow-up, the 1,991 fractures in 1,551 participants, the hazard ratios of 0.98 (0.89 to 1.08), 0.97 (0.87 to 1.07) and 1.01 (0.70 to 1.47), and the quoted conclusion.
- The effects of four doses of vitamin D supplements on falls in older adults: a response-adaptive, randomized clinical trial (Appel et al., Annals of Internal Medicine, 2021;174(2):145-156) — supports the 688 participants aged 70 and over with elevated fall risk, the 25 to 72.5 nmol/l baseline range, the 200 / 1,000 / 2,000 / 4,000 IU doses, the time-to-first-fall-or-death primary outcome, the 0.94 (0.76 to 1.15) hazard ratio at 1,000 IU, the 1.87 (1.03 to 3.41) serious-fall and 2.48 (1.13 to 5.46) hospitalised-fall hazard ratios, and the conclusion that 1,000 IU/day or higher did not prevent falls.
- Scientific opinion on the tolerable upper intake level for vitamin D, including the derivation of a conversion factor for calcidiol monohydrate (EFSA Panel on Nutrition, Novel Foods and Food Allergens, EFSA Journal, 2023;21(8):e08145) — supports the tolerable upper intake level of 100 µg/day for adults including pregnant and lactating women, the persistent-hypercalciuria critical endpoint, and the 250 µg/day lowest-observed-adverse-effect level with an uncertainty factor of 2.5.
- Vitamin D status and clinical implications in the adult population of Malaysia: a position paper by the Malaysian Vitamin D Special Interest Group (Lee et al., Osteoporosis International, 2023;34(11):1837-1850) — supports the recommendations to use serum or plasma 25-hydroxyvitamin D as the biomarker, for Malaysian laboratories to join the Vitamin D Standardization Program, to adopt the US Endocrine Society definitions, to assess identified high-risk groups, to develop a nationwide status study, and to form a national alliance covering safe sun exposure, fortification and supplementation.
- A paradoxical deficiency: lack of vitamin D with all our sunshine (Dr Jeanne Wong Sze Lyn, The Star, 12 May 2025) — supports the two quoted sentences, the attribution as consultant paediatrician and paediatric endocrinologist, the indoor-lifestyle, sun-avoidance, air-pollution and body-fat explanations, and the suggestion of 10 to 20 minutes of direct sun two to three times a week between late morning and early afternoon.