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in systolic blood pressure, and then estimated the                                           Disease-specific deaths and disability-adjusted
relationship between change in systolic blood pressure                                       life-years
and disease outcomes.14                                                                      Data on disease-specific deaths and disability-adjusted
                                                                                             life-years (DALYs) by age, sex, country, and year were
Optimal level of intake                                                                      obtained from GBD 2017. The GBD approach to
We defined the optimal level of intake as the level of risk                                  estimating cause-specific mortality and DALYs has been
exposure that minimises the risk from all causes of                                          described in detail elsewhere.25,26
death. To estimate the optimal intake for each dietary
factor, we first calculated the level of intake associated                                   Disease burden of dietary risks
with the lowest risk of mortality from each disease                                          We used the GBD comparative risk assessment approach
endpoint based on the studies included in the meta-                                          to estimate the population attributable fraction for each
analyses of the dietary relative risks. Then, we calculated                                  diet–disease pair by age, sex, country, and year.10–13 Then,
the optimal level of intake as the weighted mean of                                          we estimated the number of deaths and DALYs attri-
these numbers using the global proportion of deaths                                          butable to each dietary risk factor by multiplying the
from each disease as the weight. To reflect the                                              population attributable fraction by the total number of
uncertainty of optimal level of intake, we assumed a                                         disease-specific deaths and DALYs.
uniform uncertainty distribution of 20% above and                                               To position countries on the development continuum,
below the mean.13 For sodium, the evidence supporting                                        we used the Socio-demographic Index (SDI), which is
the selection of the optimal level of intake was                                             a summary measure calculated on the basis of lag-
uncertain.23,24 Therefore, we included a uniform distrib-                                    distributed income per capita, mean educational attain-
ution of diﬀerent optimal levels of intake in the                                            ment of individuals aged 15 years or older, and total
uncertainty estimation sampling.                                                             fertility rate among women younger than 25 years.12,13 To
                                       Exposure definition                                                                                      Optimal level of intake (optimal range of Data
                                                                                                                                                intake)                                           representativeness
                                                                                                                                                                                                  index (%)
   Diet low in fruits                  Mean daily consumption of fruits (fresh, frozen, cooked, canned, or dried fruits, excluding              250 g (200–300) per day                           94·9
                                       fruit juices and salted or pickled fruits)
   Diet low in vegetables              Mean daily consumption of vegetables (fresh, frozen, cooked, canned, or dried vegetables,                360 g (290–430) per day                           94·9
                                       excluding legumes and salted or pickled vegetables, juices, nuts, seeds, and starchy vegetables
                                       such as potatoes or corn)
   Diet low in legumes                 Mean daily consumption of legumes (fresh, frozen, cooked, canned, or dried legumes)                        60 g (50–70) per day                            94·9
   Diet low in whole grains            Mean daily consumption of whole grains (bran, germ, and endosperm in their natural                        125 g (100–150) per day                          94·9
                                       proportion) from breakfast cereals, bread, rice, pasta, biscuits, muﬃns, tortillas, pancakes,
                                       and other sources
   Diet low in nuts and seeds          Mean daily consumption of nut and seed foods                                                               21 g (16–25) per day                            94·9
   Diet low in milk                    Mean daily consumption of milk including non-fat, low-fat, and full-fat milk, excluding soy              435 g (350–520) per day                           94·9
                                       milk and other plant derivatives
   Diet high in red meat               Mean daily consumption of red meat (beef, pork, lamb, and goat, but excluding poultry, fish,               23 g (18–27) per day                            94·9
                                       eggs, and all processed meats)
   Diet high in processed meat         Mean daily consumption of meat preserved by smoking, curing, salting, or addition of                        2 g (0–4) per day                              36·9
                                       chemical preservatives
   Diet high in sugar-sweetened Mean daily consumption of beverages with ≥50 kcal per 226·8 serving, including carbonated                          3 g (0–5) per day                              36·9
   beverages                           beverages, sodas, energy drinks, fruit drinks, but excluding 100% fruit and vegetable juices
   Diet low in fibre                   Mean daily intake of fibre from all sources including fruits, vegetables, grains, legumes, and             24 g (19–28) per day                            94·9
                                       pulses
   Diet low in calcium                 Mean daily intake of calcium from all sources, including milk, yogurt, and cheese                           1·25 g (1·00–1·50) per day                     94·9
   Diet low in seafood omega-3 Mean daily intake of eicosapentaenoic acid and docosahexaenoic acid                                               250 mg (200–300) per day                         94·9
   fatty acids
   Diet low in polyunsaturated         Mean daily intake of omega-6 fatty acids from all sources, mainly liquid vegetable oils,                   11% (9–13) of total daily energy                94·9
   fatty acids                         including soybean oil, corn oil, and saﬄower oil
   Diet high in trans fatty acids      Mean daily intake of trans fat from all sources, mainly partially hydrogenated vegetable oils               0·5% (0·0–1·0) of total daily energy           36·9
                                       and ruminant products
   Diet high in sodium                 24 h urinary sodium measured in g per day                                                                   3 g (1–5) per day*                             26·2
  *To reflect the uncertainty in existing evidence on optimal level of intake for sodium, 1–5 g per day was considered as the uncertainty range for the optimal level of sodium where less than 2·3 g per day is the
  intake level of sodium associated with the lowest level of blood pressure in randomised controlled trials and 4–5 g per day is the level of sodium intake associated with the lowest risk of cardiovascular disease in
  observational studies.
  Table: Dietary risk factor exposure definitions, optimal level, and data representativeness index, 1990–2017
www.thelancet.com Published online April 3, 2019 http://dx.doi.org/10.1016/S0140-6736(19)30041-8                                                                                                                         3