Of course there are other elements to be taken into consideration like the socio economic conditions.

If we compare 2 Groups of children, the first one living in a medium size city of the Northern Italy like my home town (i.e. Ravenna) and the second one of some age living e.g. in Scampia (a district of Naples unfortunately 'governed' by Camorra), I suppose the second Group, on average, become adults before the first.

I think that some modern techniques of medicine could easily help to prove it.

Of course this kind of research it'll take some years to have the preliminary results.

Indeed it'll be necessary to follow the 2 Groups in the whole phases of pre puberty. Roughly 5/7 (both gender), 8/11 (girls milestone), 12/14 (boys milestone).

I'm looking for doctors and psichologists interested to verify my hpothesis.

Of course there are other elements to be taken into consideration like the socio economic conditions.

If we compare 2 Groups of children, the first one living in a medium size city of the Northern Italy like my home town (i.e. Ravenna) and the second one of some age living e.g. in Scampia (a district of Naples unfortunately 'governed' by Camorra), I suppose the second Group, on average, become adults before the first.

I think that some modern techniques of medicine could easily help to prove it.

Of course this kind of research it'll take some years to have the preliminary results.

Indeed it'll be necessary to follow the 2 Groups in the whole phases of pre puberty. Roughly 5/7 (both gender), 8/11 (girls milestone), 12/14 (boys milestone).

I'm looking for doctors and psichologists interested to verify my hpothesis.

This is an excellent question, very nicely introduced by @Luca Antonellini.   In addition to what @Luca Antonellini has already mentioned there is a bit more to consider.

Amazing, height influences the age of puberty.  Evidence can be found in

https://www.researchgate.net/publication/234703344_Relationships_between_age_of_puberty_onset_and_height_at_age_18_years_in_girls_and_boys

An important study of the timing of puberty over the past 50 years is given in

https://www.researchgate.net/publication/47532876_The_Timing_of_Puberty_Is_It_Changing_Does_It_Matter

Body fat and the age of puberty is explored in

https://www.researchgate.net/publication/5605739_Link_Between_Body_Fat_and_the_Timing_of_Puberty

In addition to the studies that I have cited, another profound influence on the timing of puberty is the proliferation of electonic devices such as cell phones, personal computers and television.    My conjecture is that  the timing of puberty is influenced by exposure to these media, both the information content they carry and phyiscal impact of these devices.

Article Relationships between age of puberty onset and height at age...

Article The Timing of Puberty: Is It Changing? Does It Matter?

Article Link Between Body Fat and the Timing of Puberty

It is a very interesting!

Nice question!

Early puberty leads to psycho-social difficulties.

http://www.mdpi.com/1660-4601/9/5/1791/htm

I am not much into medicine/  economics but I think I can talk some what how the psychology of child/ parent and the surrounding people get effected due to change in puberty age compare to earlier times.

Due to a lot of changes in the surrounding environment of today's child, their food habits, their education, their life style, their thoughts, their activities, their sports ....compare to earlier times, most of today's generation are entering into puberty at younger age. 

when the mental health is not evolved enough to tackle the physical changes children definitely face a lot of problems.

it builds a lot of pressure on them directly and indirectly on their parents as they have to deal with them.

Above all these things.... even in today's modern times there comes lot of rules and regulations specially for girl child when they enter into puberty...They face lot of societal problems also....which no one really notices or bothers.

its good that you have taken up such a intriguied study which when properly done taking account of all the kind of children i.e., both from urban and rural community you will definitely helping  out this delicate issue.