In my opinion, the question to ask is, what is the impact of stunted growth of adults on the health of adults, the economy, their offspring ...? If the literature shows a significant negative impact then, I think this research would be interesting

GB

My understanding is that the double burden of malnutrition refers to the concomitant experience of undernutrition, often associated to nutritional deficiencies, together with overweight or obesity, often but possibly incorrectly associated to excess consumption. In the case you suggest, the adults experienced undernutrition that potentially led them to have stunted growth, but as adults they are no longer growing. So, the stunted/overweight adult might be reflecting past undernutrition/current overweight. This would be different from an overweight/obese adult with iron-deficiency anaemia.

I would hesitate to refer to stunted-overweight adults as experiencing the double burden. Whilst an overweight adult with iron-deficiency anaemia seems to fit the definition of double burden better.

There is also ample longitudinal literature describing stunting in childhood as a risk factor for overweight later in life. This complicates further our understanding of the stunted-overweight adult.

I hope the above is useful.

Stunting has been studied widely (to an extent) and experiences from different countries have been shared. For instance, for Mozambique, around 15 years ago a study was made that showed the intergenerational impacts : socio-economic included; given the assumption that stunted children will become stunted adults (since so far evidence shows that it is irreversible) and it has deep repercussions in brain structure and function as well as its implication in health status (which in turn will also add costs to the health system expenditure).

I believe that most of the literature available is for children under five for a few reasons: 1) there is a very short window of opportunity to prevent, 2) most of funding and programs are designed to improve health status of the population by targeting children (directly or indirectly) and 3) cost-effecriveness: you have more gains by investing in a child rather than adults (looking at life expectancy and contribution to society).

I believe that further studies are required; however it would be important to determine what specifically we would be looking at and, ultimately, the purpose of the evidence.

What reference value would he use in computing adult stunting ?? 

To be pedantic ...

I find "adult stunting" to be an odd term as we generally expect linear growth to have been completed in adulthood. Stunting in adults would mean a process of losing height. It does happen during the day and with increasing age but I think you probably mean "short stature".

Now some thinking aloud ...

Short stature is typically defined as an adult height that is more than two standard deviations below the mean height for age and gender. This raises the issue of which means and which standard deviations to use. It is tempting to identify a reference / standard and we might use NHANES data for this. The problem with this approach is that, in many locations, almost all adults may have heights below USA median heights and prevalence will be very high. An alternative approach would be to use a national reference which may not be available. If these are unavailable then data from your survey may be used. The problem with this approach is that prevalence from the survey will always be about 2.3%. It is possible to use other definitions. Most states have height limits for military service below which a person is ineligible for service. You may want to use that as a reference value. The problem here is that the threshold will be designed for persons of military age and may lead to high prevalences being observed in older people. It is frequently the case that states often lower thresholds to meet demands for personnel (e.g. during the First World War, the UK and Empire forces height threshold was lowered from 160 cm to 147 cm for non-officer cadre recruits as the need for "cannon fodder" increased and special so-called "Bantam Battalions" of shorter soldiers were created).