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Sufficient dairy intake reduces fracture risk in older adults. Results of a clinical trial + interview principal investigator

Authors:
  • Dutch Dairy Association

Abstract and Figures

Dr. Sandra Iuliano and her team investigated whether the risk of falls and of bone and hip fractures decreased in older adults if they received additional daily servings of dairy. The results were startling: 33% fewer bone fractures, 46% fewer hip fractures and 11% fewer falls. Iuliano's study appeared in the renowned British Medical Journal. Read the study results plus an interview with dr. Sandra Iuliano.
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Dr. Sandra Iuliano and her team investigated whether the risk of falls
and of bone and hip fractures decreased in older adults if they received
additional daily servings of dairy. The results were startling: 33% fewer
bone fractures, 46% fewer hip fractures and 11% fewer falls. Iuliano’s
study appeared in the renowned British Medical Journal.
A
complete diet is important
for older adults, but often
proves dicult to achieve.
Older adults may start
eating less for a variety of
reasons, including illness,
reduced appetite, or diculty chewing.
But just as often psychological problems
(depression, grief), loneliness and demen-
tia and the use of medication play a role.
When older adults do not get enough
calories and micronutrients for a long
period of time, they quickly become
malnourished. This can lead to a decrease
in body weight and muscle mass and to an
increased risk of falls and bone fractures.
This while the risk of falls and bone fractures
is already much higher in older adults
because muscle and skeletal mass decreases
with age.
Intervention in older adults
Older adults often have a low intake of
the nutrients involved in good bone health
and are therefore at increased risk of bone
fractures. Dairy contains several nutrients
that contribute to good bone health,
including protein, calcium, and phosphorus.
Cheese is also a good source of vitamin
Sufficient dairy intake
reduces fracture risk
in older adults
BY ROB VAN BERKEL
Effectiveness of increasing dairy intake
Study
This article was published in Dutch in Voeding Magazine 1
|
2022
1
K2.1 A meta-analysis with 6 randomized
controlled trials found that dairy increases
bone mineral density in post-menopausal
women.2 Another meta-analysis with
7 observational studies showed that a diet
rich in dairy was associated with a 41%
lower risk of low bone mineral density.3
Australian study
Increasing dairy consumption in older
adults may be a relatively easy, inexpensive,
and safe solution to maintaining bone
health. The most reliable way to investigate
this is with a randomized controlled trial
with a sucient number of participants. In
Australia, this exact study was conducted
by Dr. Sandra Iuliano (see interview after
this article) and her team.4
Two-year trial
The trial was done in 60 care settings
in Australia with 7,195 older adults
(n=7,195).4 The average age was 89 years
and 68% of them were women. Because
the care provided by the nursing homes
had to be comparable, only nursing homes
accredited by the Australian Aged-Care
Accreditation Agency were included in
the trial. For example, a condition of
accreditation is that all older adults receive
a vitamin D supplement. Other conditions
for participation in the trial were:
Residents consumed less than 2 servings
of dairy per day
Residents’ calcium intake was less than
600 mg/day
Residents’ protein intake was less than
1 gram per kg of body weight per day
The 60 nursing homes were divided into
2 groups (see Table 1). In one group,
residents continued to receive their usual
menu (control group); in the other group,
dairy intake was increased (dairy group).
The nursing homes involved achieved
this increase in dairy intake by changing
recipes, enriching milk with milk powder,
or by oering dairy desserts and snacks
instead of foods with a lower nutritional
value. Residents with lactose intolerance
were oered lactose-free dairy products.
The total trial lasted two years and
randomization took place per nursing
home. To maintain the number of
individuals in each group, participants
who dropped out due to discharge or
death were replaced by other residents.
The primary outcome measure of the
study was the occurrence of bone fractures.
Secondary outcomes were incidence of
falls and changes in bone morphology and
biochemical parameters. Tertiary outcomes
included mortality and changes in body
composition.
Results
After two years of the trial, of the 60 nursing
homes, 54 were still involved, 25 of which
were in the dairy group and 29 in the
control group. Three nursing homes in the
dairy groups did not go through with the
trial. After 15 and 20 months, respectively,
two nursing homes were closed, but this
occurred after randomization for the trial.
One nursing home in the control group
changed owners.
Malnutrition in
the Netherlands
Malnutrition is relatively common
among older adults. A Dutch study
revealed that about 15% of older
adults in the Netherlands are
malnourished when admitted to
the hospital. However, there is
large variation in malnutrition
by medical specialty: 2 to 38%.5
Malnutrition is also common among
older adults living at home. On
average, 11-35% of people living at
home are found to be malnourished
upon admission to hospital.6
Doubling of aging
By early 2020, the Netherlands
had nearly 3.5 million people over
65, almost 20% of the population.
7
In 1990, that figure was 12.8%.
In 2040, there are expected to
be 4.8 million people over 65.
7
In addition, the number of people
over 80 is also increasing. We call
this a “doubling of aging”. In 2020,
the number of people over 80 was
838,661, almost 5% of the
popu lation. Most older adults in
the Netherlands who cannot live
independently at home are staying
in assisted living or nursing homes.
In 2019, over 115,000 Dutch people
lived in an assisted living or nursing
home.
9
Dairy group (intervention) Control group
Menu Adjusted menu with more milk, yogurt, and cheese
(562 mg of calcium and 12 grams of protein per day)
Standard menu
Protein 69 grams/day
(1.1 grams/kg body weight/day)
58 grams per day
(0.9 grams per kg body weight/day)
Calcium 1,142 mg/day 700 mg/day
Vitamin D status 72 nmol/l 72 nmol/l
Table 1: Differences and similarities between the dairy group and the control group.
2
Dietary changes
In the dairy group, dairy intake went up
from 2 to 3.5 servings per day (Figure 1).
One serving consisted of 250 ml of milk,
200 grams of yogurt, or 40 grams of
cheese. Thus, the increase in dairy is
equivalent to, for example, 250 ml of milk
and 100 grams of yogurt or 20 grams of
cheese. The higher dairy consumption
led to an increase in protein and calcium
intake (Table 1). No dierences in calorie
intake were found for the total diet.
Bone fractures, falls, and mortality
After an average follow-up of 12.6 months,
324 incidences of bone fractures had
occurred. Of these, 121 (3.7%) bone
fractures occurred in the dairy group and
203 (5.2%) in the control group. This means
that the dairy intervention led to a 33%
reduced risk of bone fractures (HR: 0.67;
95% BI: 0.48-0.93) (Figure 2). All but one
of the bone fractures were due to a fall.
A 46% reduced risk was found for hip
fractures (HR: 0.54, 95% BI: 0.35-0.83)
(Figure 2). Reduced risks were found from
5 months onwards. This means that one
bone fracture and one hip fracture per
52 and 82 older adults, respectively, are
prevented when dairy intake is increased
similar to the dairy intervention in the
trial.
The cumulative incidence of falls was 57%
(n=1,879) in the dairy group and 62%
(n=2,423) in the control group. The dairy
intervention thus led to an 11% reduced
risk of falls (HR: 0.89; 95% BI: 0.78-0.98)
(Figure 2). This means that one fall is
prevented per 17 older adults when dairy
intake is increased.
No dierence in mortality was found
between the two groups (Figure 2).
Bone morphology, biochemical
parameters, and body composition
Thanks to more complex measurements in
a subgroup, this trial also looked at bone
morphology, biochemical parameters, and
body composition (Table 2). Measurements
took place at baseline and after 12 months.
A clear dierence in CTX (a measure of
bone degradation) and IGF-1 was observed
between the groups. In addition, partici-
pants in the dairy group had higher average
bone mineral density of the lumbar vertebra
and distal radius. Whereas the control
group had lost an average of 1.4 kg per
person, the dairy group remained at the
same weight. Weight loss in the control
group consisted of 0.3 kg of lean body
mass in the arms and legs and 0.8 kg of
fat body mass.
Dairy group Control group Difference (95% BI)
Biochemical parameters (n=106) (n=83)
CTX -7.3 13.1* -20.4 (-33.2 to -7.6)
P1NP -4.7 -3.9 -0.8 (-14.6 to 12.9)
Parathormone 1.1 -0.16 1.3 (-6.7 to 9.2)
IGF-1 5.9* -2.0 7.9 (15.7 to 0.2)
Bone morphology (n=33) (n=39)
Lumbar vertebra, BMD 2.1* 0.3 1.8 (0.1 to 3.5)
Femoral neck, BMD 0.7 -1.0 1.7 (-0.3 to 3.7)
Distal radius
Total volume, BMD 0.7 -2.6* 3.3 (0.6 to 6.0)
Trabecular volume, BMD 0.9 -3.5 4.6 (0.4 to 8.2)
Cortical porosity 0.0 0.7 -0.6 (-2.3 to 1.0)
Distal tibia
Total volume, BMD -0.1 -2.1* 2.0 (-0.1 to 4.2)
Trabecular volume, BMD 0.2 -2.2 2.4 (-1.4 to 6.2)
Cortical porosity 0.4 0.7* -0.3 (-1.4 to 0.4)
Body composition (n=33) (n=39)
Body weight 0.6 -1.9* 2.5 (0.6 to 4.1)
Lean body mass -0.2 -0.4 0.3 (-0.9 to 1.6)
Arms and legs 0.3 -1.7* 2.0 (0.02 to 4.1)
Fat body mass 3.8 -3.3* 7.3 (0.1 to 14.5)
Table 2: Mean percentage change in biochemical parameters, bone morphology, and body composition from
baseline to month 12.
CTX = C-terminal telopeptide (marker for bone degradation), P1NP = Total procollagen type 1 N-terminal
propeptide (marker for bone formation), IGF-1 = Insulin-like growth factor 1, BMD = Bone mineral density.
* Significant difference compared to baseline within group (p<0.05
Bold = Significant difference between the two groups (p<0.05).
Figure 1: Average dairy consumption of the dairy group and the control group at baseline
and during the 2-year trial period. Orange: control group, blue: intervention group.
* Significant difference compared to the control group (p<0.05).
136912 15 18 21 24
Daily portions
Months
0
1
2
3
4
5
******
Effectiveness of increasing dairy intake
Study
3
References
1 Vermeer C, Raes J, van ‘t Hoofd C, et al. Menaquinone Content of Cheese. Nutrients. 2018 Apr 4;10(4):446.
2 Shi Y, Zhan Y, Chen Y, Jiang Y. Effects of dairy products on bone mineral density in healthy postmenopausal women:
a systematic review and meta-analysis of randomized controlled trials. Arch Osteoporos. 2020 Mar 18;15(1):48.
3 Fabiani R, Naldini G, Chiavarini M. Dietary Patterns in Relation to Low Bone Mineral Density and Fracture Risk:
A Systematic Review and Meta-Analysis. Adv Nutr. 2019 Mar 1;10(2):219-236.
4 Iuliano S, Poon S, Robbins J, et al. Effect of dietary sources of calcium and protein on hip fractures and falls in older
adults in residential care: cluster randomised controlled trial. BMJ. 2021 Oct 20;375:n2364.
5 Kruizenga H, van Keeken S, Weijs P, et al. Undernutrition screening survey in 564,063 patients: patients with a
positive undernutrition screening score stay in hospital 1.4 d longer. Am J Clin Nutr. 2016 Apr;103(4):1026-32.
6 Schilp J, Kruizenga HM, Wijnhoven HA, et al. High prevalence of undernutrition in Dutch community-dwelling older
individuals. Nutrition. 2012 Nov-Dec;28(11-12):1151-6.
7 https://www.cbs.nl/nl-nl/visualisaties/dashboard-bevolking/leeftijd/ouderen
8 https://www.cbs.nl/nl-nl/longread/statistische-trends/2020/bevolkingsprognose-2020-2070-/5-toekomstige-
ontwikkeling-van-de-bevolking
9 https://www.cbs.nl/nl-nl/maatwerk/2020/13/aantal-bewoners-van-verzorgings-en-verpleeghuizen-2019
10 Tang BM, Eslick GD, Nowson C, et al. Use of calcium or calcium in combination with vitamin D supplementation
to prevent fractures and bone loss in people aged 50 years and older: a meta-analysis. Lancet. 2007 Aug
25;370(9588):657-66.
Figure 2: Cumulative risks of bone fractures, hip fractures, fall incidence, and mortality in the dairy group and the control group.
Cumulative risk of incidence
0
0.025
0.050
0.075
0.100
0.125
Intervention group Control group
All bone fractures
Cumulative risk of incidence
0
0.025
0.050
0.075
0.100
0.125
Intervention group Control group
Hip fractures
Cumulative risk of incidence
0
0.2
0.4
0.6
0.8
1.0
Intervention group Control group
05 10 15 20 25
Months
Cumulative risk of incidence
0
0.1
0.2
0.3
0.4
0.5
Intervention group Controlegroep
Mortality rate
05 10 15 20 25
Months
Falls
Beneficial effect
At the start of the study, all older adults
had lower intakes of protein and calcium
than recommended. The authors indicate
that the beneficial eect would have been
less likely had the older adults eaten
according to the recommendations. One
explanation for the beneficial eects of the
dairy intervention is that it slowed down
bone loss and reduced microstructural
decline. A meta-analysis into the eect of
supplementation with calcium (with or
without vitamin D) on incidence of bone
fractures in people over 50 shows a similar
picture.10 A beneficial eect was also
found at a previous calcium intake of less
than 700 mg/day.
Limitations
This study also had some limitations. Less
than half of the residents had a follow-up
of more than 15 months. Nevertheless,
a reduced risk was found after only
5 months. Furthermore, follow-up on
the dairy intervention was monitored in
716 residents (10%).
Conclusion
Older adults often have an insucient
intake of protein and calcium. This study
shows that increasing dairy consumption
in older adults from 2 to 3.5 servings per
day increases protein and calcium intake.
A highly beneficial eect of the intervention
is that the risk of bone fractures and falls
in this vulnerable group of people is greatly
reduced.
According to the authors, the study has
broad implications for healthcare policies
to prevent bone fractures in care settings
and possibly beyond.
4
Dr. Sandra Iuliano
Interview
BY DR. STEPHAN PETERS (DUTCH DAIRY ASSOCIATION)
‘By simply improving the quality of nutrition, we can
make a big difference in the lives and health of older
adults in aged care’
What are the main results of
your study?
Older adults living in care facilities in
Australia consume, on average, about
2 servings of dairy per day. When we
increased that intake to 3.5 servings –
the recommended amounts – we saw
a relative risk reduction of 33% for
all types of fractures, of 46% for hip
fractures and of 11% for falls. We saw no
change in the number of deaths. This is
scientific evidence that the consumption
of foods high in calcium and protein
(such as milk, yogurt, cheese) in the
recommended amounts reduces the risk
of bone fractures in older adults compared
to an intake below the recommended
amounts. Australian guidelines recom-
mend a daily intake of 4 servings of dairy
for older women and 3.5 servings for
older men, so our results are in line with
that. A serving in Australia is 250 ml of
milk, 40 g of cheese, and 200 g of yogurt.
How do you explain these results?
The results show that the consumption
of dairy products in the recommended
amounts is related to slowing the decline
in volumetric bone mineral density:
no significant loss was apparent after
12 months. In older adults who consumed
fewer dairy products, we did see a loss
in volumetric bone mineral density. Also,
the muscles in the arms and legs of the
dairy group remained stable, while muscle
loss occurred in the control group. These
dierences may explain the beneficial
eects we observed because they go
beyond the eects of the nutrients in
dairy on bone health. We saw that muscle
mass and strength were preserved, and
this too may account for the reduction in
fractures and falls in the older adults in
the dairy group.
5
Why did you conduct this study?
Dairy is known to protect against
fractures, right?
The link between dairy intake and
fractures was actually an assumption
until now. Based on intervention studies,
it was assumed that dairy intake has a
beneficial eect on bone growth and
mineralization and on reducing bone
decline. But results for fractures were
extrapolated from observational and
exploratory studies that described only
correlations. The necessary evidence
based on a properly conducted,
randomized clinical trial that confirmed
these assumptions had never been
provided until our study.
What was your role in the study?
I was the principal investigator;
I designed and led the study. I took
care of all the care settings and
participants and maintained contact
with the management of the care
settings. I was not involved in testing
or analyses, because I would have
known which groups the dierent
institutions were assigned to and I
needed to stay in touch with facility
management.
What did you learn and experience
while conducting this study?
What surprised me the most was that by
simply improving the quality of nutrition
we can make such a big dierence to the
lives and health of older adults in aged
care. I now have in my hands the evidence
with which to advocate for changes in
food provision in aged care. And I have
already presented the evidence to the
“Royal Commission into Aged Care”
who are investigating this on behalf of
the government. This study has given me
a voice and I can now influence change
in a positive direction.
Which organizations funded
the study and did that affect
the outcome?
The study was conducted by the Univer-
sity of Melbourne and was partly funded
by dairy organizations. The funders had
no say in the design and execution of the
study, nor in the publication of the
results. I am very grateful for the funding
from the industry, because without that
support the project would not have been
carried out. We would not have been able
to demonstrate the importance of good
nutrition for the health of older adults.
You could also have included an
alternative plant-based group in
your study. Why did you not do so?
And would you have expected the
same results?
There are a couple of reasons for this.
First, an additional group would have
doubled the cost of the study. In addition,
older adults do not have the ability to
consume the amount of plant-based
calcium sources that would be required
to have sucient calcium. The average
older adult in our study consumed less
than 2 kg of food per day. In order to get
the recommended amount of calcium
they would have to consume 4 kg of
plant-based calcium sources! We asked
the residents what they wanted to eat
and paid attention to their preferences.
Many of the older adults had grown up
with foods such as dairy products.
Therefore, we oered them products
that they already liked to eat.
Can you provide an example of a 2 kg daily diet with dairy from your study, and a 4 kg daily diet with plant-based
alternatives that contains the same amount of calcium?
Meal Intervention menu Plant-based alternative
Breakfast Cereal with fortified milk (300),
2 pieces of toast (100),
portion of fruit (calcium 400 mg)
Cereal with plant-based milk (must be enriched with Ca)*,
2 pieces of toast, portion of fruit (calcium 400 mg)
* If not: 4 pieces of toast (200), 2 oranges (100),
6 figs (100)
Lunch Cup of soup + parmesan cheese (200),
2 slices of roasted meat (100 g),
3x vegetables (1/2 cup each)
Dessert: stewed fruit with custard (200)
(calcium 400 mg)
Cup of soup,
300 g tofu (100),
3x vegetables (1 cup each) (250)
Dessert: 60 g dried apricots and 60 g raisins (sautéed)
(70) (calcium 420 mg)
Dinner Quiche with cheese and vegetables
(calcium 200 mg)
2 cups green leafy vegetables
(calcium 200 mg)
Snacks 40 g cheese and biscuits
(calcium 300 mg)
120 g almonds
(calcium 300 mg)
6
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p>To assess the antifracture efficacy and safety of a nutritional intervention in institutionalised older adults replete in vitamin D but with mean intakes of 600 mg/day calcium and <1 g/kg body weight protein/day. Two year cluster randomised controlled trial. 60 accredited residential aged care facilities in Australia housing predominantly ambulant residents. 7195 permanent residents (4920 (68%) female; mean age 86.0 (SD 8.2) years). Facilities were stratified by location and organisation, with 30 facilities randomised to provide residents with additional milk, yoghurt, and cheese that contained 562 (166) mg/day calcium and 12 (6) g/day protein achieving a total intake of 1142 (353) mg calcium/day and 69 (15) g/day protein (1.1 g/kg body weight). The 30 control facilities maintained their usual menus, with residents consuming 700 (247) mg/day calcium and 58 (14) g/day protein (0.9 g/kg body weight). Group differences in incidence of fractures, falls, and all cause mortality. Data from 27 intervention facilities and 29 control facilities were analysed. A total of 324 fractures (135 hip fractures), 4302 falls, and 1974 deaths were observed. The intervention was associated with risk reductions of 33% for all fractures (121v203; hazard ratio 0.67, 95% confidence interval 0.48 to 0.93; P=0.02), 46% for hip fractures (42v93; 0.54, 0.35 to 0.83; P=0.005), and 11% for falls (1879v2423; 0.89, 0.78 to 0.98; P=0.04). The risk reduction for hip fractures and falls achieved significance at five months (P=0.02) and three months (P=0.004), respectively. Mortality was unchanged (900v1074; hazard ratio 1.01, 0.43 to 3.08). Improving calcium and protein intakes by using dairy foods is a readily accessible intervention that reduces the risk of falls and fractures commonly occurring in aged care residents. </p
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Low bone mineral density (BMD) and osteoporosis-related fractures constitute a considerable public health burden. Several studies have demonstrated the association between diet and bone health. We performed a systematic review to provide an estimate of the association between different dietary patterns defined through the use of a posteriori methods and fracture or low BMD risk. A literature search on PubMed, Web of Science, and Scopus databases, up to March 2018, was performed to identify all eligible case-control, prospective, or cross-sectional studies involving subjects of both sexes and any age. Random-effects models were used. Heterogeneity and publication bias were evaluated. Stratified analyses were conducted on study characteristics. The meta-analysis includes 20 studies and identifies 3 prevalent dietary patterns: "Healthy," "Milk/dairy," and "Meat/Western." From the 10 studies on fracture, adherence to the "Healthy" pattern reduced the risk, particularly in older people (OR: 0.79; 95% CI: 0.66, 0.95; P = 0.011) and in Eastern countries (OR: 0.64; 95% CI: 0.43, 0.97; P = 0.037), whereas the risk increased with the "Meat/Western" pattern, especially for older people (OR: 1.11; 95% CI: 1.04, 1.18, P = 0.001), in those with hip fractures (OR: 1.15; 95% CI: 1.05, 1.25; P = 0.002), and in Western countries (OR: 1.10; 95% CI: 1.07, 1.14; P < 0.0001). Analyses on low BMD showed a reduced risk in the "Healthy" pattern, particularly for younger people (OR: 0.62; 95% CI: 0.44, 0.89; P = 0.009). The "Meat/Western" pattern increased low BMD risk, especially in older people (OR: 1.31; 95% CI: 1.05, 1.64; P = 0.015). The "Milk/dairy" pattern resulted in the strongest reduction in low BMD risk; when stratifying, this effect remained significant (e.g., older women-OR: 0.57; 95% CI: 0.46, 0.70; P < 0.0001). Nutrition is an important modifiable factor affecting bone health. The "Healthy" and "Milk/dairy" patterns are associated with a reduced risk of low BMD and fracture. In contrast, the "Western" pattern is inversely associated.
Article
Osteoporotic bone fractures are becoming an increasing burden worldwide-socially and economically-as the population ages. Supplemental calcium, alone or combined with vitamin D, has been proposed as a relatively inexpensive way of preventing osteoporotic bone loss, but whether it lowers the risk of fracture remains uncertain. Meta-analyses have, up to now, yielded inconsistent results. The present meta-analysis is based on 29 randomized trials totalling 63,897 adults aged 50 years and older. Seventeen trials numbering 52,625 persons reported fracture as an outcome, while 23 trials comprising 41,419 individuals reported bone mineral density (BMD) as an outcome. All trials compared calcium, alone or combined with vitamin D supplementation, with a placebo. In trials reporting fracture as an outcome, supplementation was associated with a 12% reduction in fractures of all types (risk ratio, 0.88; 95% confidence interval, 0.83-0.95; P = 0.0004). In trials reporting BMD as an outcome, treatment correlated with a reduced rate of bone loss averaging 0.54% (0.35%-0.73%; P < 0.0001) at the hip and 1.19% (0.76%-1.61%) at the spine. The reduction in fracture risk was significantly greater (by 24%) in trials with high compliance rates. A more substantial treatment effect was noted with calcium doses of 1200 or more than with lower doses (0.80 versus 0.94; P = 0.006), and with vitamin D doses of at least 800 IU (0.84 versus 0.87; P = 0.03). Neither gender nor a history of fracture influenced observed treatment effects. Adding vitamin D to calcium also did not alter treatment effects. Subjects with relatively low serum vitamin D levels had a greater risk reduction, but the difference was not significant. Lesser risk reductions were noted in persons 50-70 years of age than in those older than 70. These findings demonstrate that supplemental calcium, alone or combined with vitamin D, can prevent osteoporotic bone fractures. Analysis of the estimated number needed to treat shows that 63 patients will have to be treated over 3.5 years to prevent a single fracture. At least 1200 mg of calcium and 800 IU of vitamin D are recommended for combined supplementation.