The paper discusses the content of elements in hair of subjects studied over several years. The study was performed on 5 subjects (N=28) that lived together or were family related. The elemental composition of hair of the studied subjects was compared with the average content of the population living in the same urban area (Wrocław city, south-west Poland), with the population of a non-industrialized area in Poland (Silesian Beskid), as well as with the population of north-east Sweden and Rio de Janeiro. When comparing the composition of hair from the studied subjects with the people living in the same city, it was found that the differences resulted mainly from different living habits (Na, Si, Co, Fe, Mn, Zn) and local exposure (Pb, Cd, Al). When comparing with the reference material for unexposed population, it was found that the studied subjects were exposed to Al. Time profile of element contents in hair of a given person showed that the level changed significantly (even several fold) with changes of living habits or environmental exposure. Also, it was found that there were similar tendencies in the accumulation of the majority of elements by people that lived together. The effect of living habits on the level of a given element was found to be stronger than the influence of either sex or family relationship. The paper also discusses inter-element interactions within the studied group. Statistically significant (p<0.05) correlations were found between elements that occur together: Ca-Mg, Fe-Mn, Na-K, Co-K, Au-Pt, Cd-Pb. In order to determine the influence of various elements on the content of another element, linear multiple regression was performed that revealed the following relationships: Ca=f(Mn, Sr), Na=f(K, Mn), K=f(V, Ti).